Data Loading...
DUAL LANGUAGE SCIENCE FORM 1 Flipbook PDF
DUAL LANGUAGE SCIENCE FORM 1
112 Views
40 Downloads
FLIP PDF 167.13MB
DUAL LANGUAGE PROGRAMME
FORM 1
FT071002
RD NDA
SEKOLAH M EN
LA YS IA
KS S M
E
H
SCIENCE
ISBN 978-967-14472-5-3
STA
A NG
FORM 1
KE
SCIENCE
UM
K UR IKU L
1
M EN MA TE AN RIAN PENDIDIK
RUKUN NEGARA
Bahawasanya Negara Kita Malaysia mendukung cita-cita hendak; Mencapai perpaduan yang lebih erat dalam kalangan seluruh masyarakatnya; Memelihara satu cara hidup demokrasi; Mencipta satu masyarakat yang adil di mana kemakmuran negara akan dapat dinikmati bersama secara adil dan saksama; Menjamin satu cara yang liberal terhadap tradisi-tradisi kebudayaan yang kaya dan pelbagai corak; Membina satu masyarakat progresif yang akan menggunakan sains dan teknologi moden; MAKA KAMI, rakyat Malaysia, berikrar akan menumpukan seluruh tenaga dan usaha kami untuk mencapai cita-cita tersebut berdasarkan prinsip-prinsip yang berikut:
KEPERCAYAAN KEPADA TUHAN KESETIAAN KEPADA RAJA DAN NEGARA KELUHURAN PERLEMBAGAAN KEDAULATAN UNDANG-UNDANG KESOPANAN DAN KESUSILAAN (Sumber: Jabatan Penerangan, Kementerian Komunikasi dan Multimedia Malaysia)
KURIKULUM STANDARD SEKOLAH MENENGAH
SCIENCE FORM 1
Writers Vengadesh Periasamy Noraini binti Abdullah Fauziah binti Mo’men Editors Nadiatulaini binti Azenan Chan Chon Wah Designer Mohamad Akmal Ariff bin Kamarudin Illustrator Baharin bin Abd. Hamid
2016
SERIAL BOOK NO. : 0197 KPM2016 ISBN 978-967-14472-5-3 First Published 2016 © Ministry of Education Malaysia All rights reserved. No part of this publication may be produced, stored in any retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without prior permission of the Director General of Education, Ministry of Education Malaysia. Negotiation is subject to the calculation of royalty or honorarium. Published for Ministry of Education Malaysia by: Karangkraf Network Sdn.Bhd. Lot 2, Jalan Sepana 15/3, Off Persiaran Selangor, Seksyen 15, 40200 Shah Alam, Selangor Darul Ehsan. Telephone: 603-5101 3836 Fax: 603-5101 3685 Email: [email protected] Website: www.karangkraf.com Design and typesetting by: Karangkraf Network Sdn.Bhd. Font type: Book Antiqua Font size: 11 pt. Printed by: Ultimate Print Sdn.Bhd. Lot 2, Jalan Sepana 15/3, Off Persiaran Selangor, Seksyen 15, 40200 Shah Alam, Selangor Darul Ehsan.
ii
ACKNOWLEDGEMENT The publisher would like to thank the following organisations for their invaluable assistance and cooperation in the preparation of this book: Committee members of Quality Control, Textbook Division, Ministry of Education Malaysia Curriculum Development Division, Ministry of Education Malaysia Internal Affairs and Research Office, Chief Minister’s Department, Sabah Department of Statistics Malaysia
Contents Theme 1: Scientific Methodology
1
1
Introduction to Scientific Investigation
2 1.1 Science is Part of Daily Life 4 1.2 Your Science Laboratory 9 1.3 Physical Quantities and Their Units 15 1.4 The Use of Measuring Instruments, Accuracy, Consistency, Sensitivity and Errors 18 1.5 Density 28 1.6 Steps in a Scientific Investigation 33 1.7 Scientific Attitudes and Values in Carrying Out Scientific Investigations 37 Summative Practice 1 41
Chapter
Theme 2: Maintenance and Continuity of Life 43
Chapter
2
Cell as the Basic Unit of Life
3
Coordination and Response
2.1 Cell – Structure, Function and Organisation 2.2 Cellular Respiration and Photosynthesis Summative Practice 2
Chapter
3.1 Homeostasis in Living Things Summative Practice 3
Theme 3 : Exploration of Elements in Nature
Chapter
70 72 85
4
Reproduction 4.1 Sexual and Asexual Reproduction 4.2 Human Reproductive System 4.3 The Menstrual Cycle 4.4 Fertilisation and Pregnancy 4.5 Factors Affecting the Development of a Foetus and Baby 4.6 Infertility and Contraception 4.7 Plant Reproduction Summative Practice 4 Chapter
5
Matter
5.1 Matter in Nature 5.2 Three States of Matter Summative Practice 5
44 46 59 67
88 90 97 104 107 111 115 119 133
135 136 138 145 159 iii
Chapter
6
Periodic Table
6.1 Classification of Elements 6.2 Mixtures 6.3 Compounds Summative Practice 6
Chapter
7
Air
7.1 Composition of Air 7.2 Combustion 7.3 Air Pollution Summative Practice 7
194 196 204 208 214
Theme 4: Energy and Sustainability of Life
Chapter
8
Theme 5 Exploration of Earth and Space
Chapter
9
219
Light and Optics
8.1 The Usage of Mirrors 8.2 Properties of Light 8.3 Reflection of Light 8.4 Refraction of Light 8.5 Dispersion of Light 8.6 Scattering of Light 8.7 Addition and Subtraction of Light Summative Practice 8
Earth
9.1 The System and Structure of the Earth 9.2 Composition of the Earth 9.3 Main Processes of the Earth 9.4 Geohazard Phenomena 9.5 Age of the Earth 9.6 Earth Resources and Applied Geology Summative Practice 9
162 164 176 185 191
220 222 229 2 30 233 236 239 2 41 250
253 254 256 261 263 265 268 270 275
Answers
278
Glossary
284
Reference
287
Index
288
iv
Introduction Introduction
T
he Science Form 1 Kurikulum Standard Sekolah Menengah (KSSM) Textbook is written for Form 1 students based on Dokumen Standard Kurikulum dan Pentaksiran Tingkatan 1 prepared by the Ministry of Education. KSSM is developed to cater to the new policies under the Malaysian Education Blueprint 2013 - 2025. For the successful implementation of KSSM, this book is written with more emphasis on thinking skills, information and communication skills, decision-making and problem-solving skills so that students can master the skills needed in the 21st century. To achieve this objective, this book incorporates special features as follows:
21st Century Skills 21
CPS
21
ISS
21
ICS
Critical Thinking & Problem Solving Skills Interpersonal & Self-Reliance Skills Information & Communication Skills
Science Exploration Provides extra information related to the topics studied.
Science in Life Applications of science in the daily life of students.
My Malaysia Latest information regarding science in Malaysia.
QR code Download the free app from Google Play to your mobile smartphone device. Scan this QR code with your mobile smartphone device to obtain additional information. (Websites in the public domain proposed in this book may be subject to change from time to time). v
I Can Remember! Formulae or important information for students to remember.
Science Careers Information on careers related to science.
Formative Practice Provides questions to test students’ understanding at the end of each subtopic.
Brain Teaser Questions that challenge students’ way of thinking.
Future Studies Studies for the development of technology in the future.
History Corner Information about the history of science.
Science Today Latest information or news regarding science.
vi
There are five types of activities in this book
Experiments
Creation and innovation
Discussion Inquiry-based activities Technology-based activities
At the end of each chapter Self-Reflection Simple checklist of learning contents for students’ reference.
Concept Map Summary of each chapter is presented in the form of concept map.
The Next Challenge Level 5 and level 6 HOTS questions.
Summative Practice Provides questions to test students’ understanding at the end of each chapter.
HOTS Questions Applying
Analysing Evaluating
Creating vii
How to scan three-dimensional animations
1
2
Step 1
Download the free QR reader application from the App Store or Play Store.
Step 2
Download the free AR Buku Teks application by scanning the QR Code below.
or
3
Step 3
Find pages that have this icon. Three-dimensional animation Key: Use the QR reader application to access websites and videos
360o
4
Step 4
Then, scan the image on the page with your smartphone or tablet and enjoy the three-dimensional animations!
viii
Use the AR BUKU Teks application to view 360° pictures
Chapter 1: Introduction to Scientific Investigation Pengenalan kepada Penyiasatan Saintifik
1
gy lo o d o h t e M ic if t n ie Sc
Do you realise that our life is based on science? This includes the food we eat, the clothes we wear, our modes of transportation and the energy we use.
Chapter 1
1
Chapter
1
Introduction to Scientific Investigation
What is science? What are physical quantities? How do we measure density?
Let’s study: Science is Part of Daily Life Your Science Laboratory Physical Quantities and Their Units
2
Chapter 1
The Use of Measuring Instruments, Accuracy, Consistency, Sensitivity and Errors Density Steps in a Scientific Investigation Scientific Attitudes and Values in Carrying Out Scientific Investigations
Chapter 1: Introduction to Scientific Investigation Pengenalan kepada Penyiasatan Saintifik
SCIENCE BULLETIN
ORIGIN OF SCIENC
T
E
he word ‘science’ origi nates from the Latin wo rd ‘Scientia’ which means the know ledge of natural phenom ena. People in the olden days observed natural phenomena such as rainbow and thunder. They explaine d how natural phenom ena occur based on their understanding. Ho wever, their understan ding is usually full of myths and beliefs. Reali sing this weakness, scien tists began to carry out systematic experim ents according to the rig ht scientific steps. This enables collection of data to make conclus ions on how natural phenomena oc cur.
Natural phenomena Systematic error Systematic observation and experiments Careers in science Water displacement Hazard symbols
Variables S.I. units Hypothesis Prefixes Inference Random error Values
Chapter 1
3
1.1
Science is Part of Daily Life
Let’s learn • • • • • • •
Relate daily activities to science. Generalise the meaning of science. Summarise the importance of science in everyday life. Describe the fields of science. Communicate about careers related to science. Relate subjects to be studied in science to careers of interest. Describe innovation in technology.
What is Science? Observe the phenomena around you.
a
nomen hese phe How do t happen?
Photograph 1.1 Natural phenomena
In order to understand the factors involved and how natural phenomena occur, we have to carry out scientific investigations. Science is a discipline that involves systematic observations and experiments of natural phenomena.
4
Chapter 1
Chapter 1: Introduction to Scientific Investigation Pengenalan kepada Penyiasatan Saintifik
Observe our daily activities.
Photograph 1.2 Daily activities
Does science change or affect our daily activities? Give a few other examples of daily activities that are related to science.
The Importance of Science in Everyday Life The examples of the importance of science in everyday life are shown in the figure below. The Importance of Science in Everyday Life TV satellite
Tall buildings
Contributes to the area of engineering such as construction of tall buildings.
Invention of satellites has made communication more effective and faster.
Hydroponic method
Increases crop yields by invention of fertilisers, pesticides and hydroponic method.
Vaccine
Discovery of vaccines and antibiotics in the field of medicine helps in controlling infectious diseases and reduces death rate.
Figure 1.1 Examples of the importance of science in everyday life Chapter 1
5
6
Chapter 1
Example: Engineering
Study of energy and its influence on matter
Physics
Examples: Zoology, microbiology, physiology, botany
Study of living things
Biology
Examples: Geochemistry, geomorphology and geophysics
Study of rocks, soil and minerals
Geology
Figure 1.2 Classification in the fields of science
Examples: Pharmacology, forensics, toxicology
Study of matter and its reactions
Chemistry
Fields in Science
Example: Astrophysics
Study of planets, stars and other objects in the universe
Astronomy
Example: Hydrometeorology
Study of weather and climate change
Meteorology
Science can be divided into various fields. The tree map below shows some examples of important fields in science.
Fields in Science
Chapter 1: Introduction to Scientific Investigation Pengenalan kepada Penyiasatan Saintifik
Careers in Science What is your ambition? List the science subjects that you need to study in order to achieve your ambition. I want to become an engineer. What are the subjects that I need to study?
I want to become a doctor. What are the subjects that I need to study?
Figure 1.3 Students’ ambitions
A few examples of careers in science are shown in the tree map below. Careers in Science
Physics
Biology
Chemistry
Geology
Astronomer
Medical doctor
Pharmacist
Geologist
Oceanographer
Botanist
Oceanographer
Teacher
Teacher
Zoologist
Teacher
Meteorologist
Teacher
Forensic scientist
Engineer
Oceanographer
Chemist
Physicist
Microbiologist Biologist Figure 1.4 Careers in science
Engineer
Doctor
Pharmacist
Photograph 1.3 Careers in science
Geologist
Chapter 1
7
Innovation in Technology Most machines and inventions that we use every day are scientific innovations. For example, cars, aeroplanes, telephones and computers. These machines and instruments help us solve problems in our life. Photograph 1.4 Development of technology
1.1
21
ICS
Aim: To give examples of innovations in technology to solve problems in life Instruction 1. In groups, search for examples of innovations in technology. Information can be obtained from the Internet, magazines, newspapers or from other sources. 2. Discuss the information that you have collected and present your discussion in class by using multimedia presentation such as PowerPoint. 3. Discuss how robots can help us in our life. Look at Figure 1.5.
I can help my master to repair electrical instruments.
I can help my master to clean the house.
Figure 1.5 Robots can help us in our daily life
Do you know? The Nobel Prizes in Science are awarded every year to the outstanding scientists in fields of science every year in Stockholm, Sweden. You can browse the following website for further information. Nobel prize http://www.nobelprize.org
8
Chapter 1
Photograph 1.5 The Nobel Prize
Chapter 1: Introduction to Scientific Investigation Pengenalan kepada Penyiasatan Saintifik
1.1 1. Tick (✓) on natural phenomena.
Growth of a baby
Construction of tall buildings
Discovery of new medicine
The occurrence of day and night
2. Fill in the blanks with the correct answers. and (a) Investigation of science involves systematic of natural phenomena. (b) The recent discovery of vaccines to treat dengue infection is a science by microbiologists. knowledge applied in the field of 3. List three fields in science and their related careers.
1.2
Your Science Laboratory
Let’s learn • Identify and state the functions of apparatus. • Identify symbols and examples of hazardous materials in the laboratory. • Draw and label apparatus commonly used in the laboratory and classify based on how it is used. • Justify the regulations and safety measures in the laboratory.
T
he science laboratory is a room equipped to conduct scientific investigations and experiments. There are many types of materials and apparatus found in the laboratory, for example, measuring cylinder, retort stand and pipette.
Photograph 1.6 Science laboratory Chapter 1
9
Table 1.1 The apparatus commonly used in a laboratory and their functions
Apparatus
Function Boiling tube
To heat small amounts of chemicals
Test tube
To hold small amounts of chemicals
Apparatus
Function To measure volume of liquid accurately Burette
To measure a fixed volume of liquid Beaker
Conical flask
Pipette
To hold larger amounts of chemicals
Tripod stand
Wire gauze
Flat-bottom flask
Filter funnel
To measure volume of liquid Measuring cylinder 10
Chapter 1
To support apparatus during heating
To spread heat evenly during heating
To filter or separate insoluble solids from mixtures
To contain gas Gas jar
Chapter 1: Introduction to Scientific Investigation Pengenalan kepada Penyiasatan Saintifik
Retort stand with clamp
To hold or support apparatus
To evaporate
Evaporating excess solvent dish
1.2 Aim: To identify the apparatus commonly used in the laboratory Instruction 1. In groups, observe the apparatus commonly used in the laboratory. 2. Identify the apparatus and state their functions. Record them in your practical book. 3. Draw and label the apparatus in your practical book. 4. Then, discuss the classification of the apparatus according to their usage. 5. Present your discussion in class by using a tree map.
Symbols of Hazardous Materials in the Laboratory
Have you seen the symbol as in Figure 1.6? What is the meaning of the symbol?
Science Exploration
Figure 1.6 A hazard symbol
Some chemicals like potassium and lithium will react if exposed to air. So, these chemicals must be kept in paraffin oil.
Most chemicals that we use in the laboratory are hazardous. We must observe the hazard symbols on chemical bottles before using them to prevent accidents.
Photograph 1.7 Hazardous materials with hazard symbols
Photograph 1.8 Lithium is kept in paraffin oil Chapter 1
11
Hazard Symbols Irritant
Chemicals which irritate give out vapour or fumes that will hurt the eyes, nose and throat. AVOID inhaling the vapour or fumes. Use the chemicals inside a fume chamber. Examples: chloroform and ammonia. Radioactive
Radioactive materials that emit radioactive rays can cause cancer. Examples: uranium and plutonium. Corrosive
These chemicals are corrosive. DO NOT touch these chemicals because it will burn your skin. In case of contact with the skin, wash the affected part with lots of water. Examples: concentrated acid and alkali. Poison / Toxic
This chemical is poisonous or toxic. DO NOT drink, eat, smell or taste this chemical. Examples: mercury and chlorine. Explosive
This chemical is explosive. Use this chemical according to the instructions CAREFULLY. Examples: hydrogen gas and butane gas.
This chemical easily vaporises and is flammable. KEEP AWAY this chemical from fire or heat sources. Use this chemical according to instructions carefully. Examples: alcohol and petrol.
Flammable
Figure 1.7 Hazard symbols
1.3
21
CPS
Aim: To identify the hazard symbols Instruction 1. Work in groups. Identify the hazard symbols found in the laboratory. 2. Discuss the information gathered. 3. Present the discussion in class.
B Photograph 1.9 Chemicals in a laboratory
12
Chapter 1
How would you transfer 10 ml of a corrosive chemical into a beaker? What will happen if you use a plastic beaker for this purpose? Why?
Chapter 1: Introduction to Scientific Investigation Pengenalan kepada Penyiasatan Saintifik
Rules and Safety Measures in the Laboratory To prevent unwanted incidents, we should follow the rules and safety measures in the laboratory.
Laboratory Rules Do not enter the laboratory without permission. Never start an experiment without the teacher’s instructions. Read and understand the instructions of the experiment beforehand. Use the chemicals and apparatus correctly and carefully. Eating, drinking and playing are prohibited in the laboratory. Do not take the apparatus and chemicals out of the laboratory. After using, keep the apparatus and chemicals in their original places. Make sure the place to conduct the experiments is always neat and clean. Wash all the apparatus and throw away waste materials according to the correct procedures. Wash your hands with soap and water before leaving the laboratory. Safety Measures when Using Chemicals and Apparatus
Do not point the mouth of the test tube at your face or at other people.
Keep highly flammable chemicals away from any heat sources.
Use safety goggles when mixing or heating chemicals.
Do not taste or smell anything unless allowed by the teacher.
Chapter 1
13
If an accident occurs, do not panic. Take the necessary actions as demonstrated in the situations below: Spilled chemicals should be reported to the teacher.
1
2
Caution, avoid contact with the chemical.
Din, run quickly! There is a fire! I have already turned off the electricity. Let us inform our teacher.
3
Remember, Farah, if you accidentally come into contact with any chemicals, you need to rinse it off with plenty of water.
1.4 Aim: To discuss the rules and safety measures in the laboratory Instruction 1. Work in groups. Each group has to look for information about one of the topics given below: (a) Rules in a laboratory (b) Safety measures in a laboratory (c) Steps to prevent fire in a laboratory (d) Actions to be taken in the event of an accident in a laboratory 2. Discuss the information gathered in your group and present it in the class.
1.2 1. Draw the following apparatus. (a) Flat-bottom flask (b) Conical flask (c) Boiling tube (d) Measuring cylinder 2. (a) What is the meaning of the hazard symbols below? (i)
(ii)
(iii)
(iv)
(v)
(b) State two examples of chemicals with the hazard symbol in (a)(i). 3. Suhaimi sees a small fire on the laboratory table. What actions should he take?
14
Chapter 1
Chapter 1: Introduction to Scientific Investigation Pengenalan kepada Penyiasatan Saintifik
1.3
Physical Quantities and Their Units
Let’s learn • Identify and use the correct units for different physical quantities. • Identify the symbols and values of prefixes used in measurement. • Convert base quantity units for mass, length and time such as grams to kilograms, centimetres to metres, seconds to hours and vice versa. • Justify the importance of the use of S.I. units in daily life.
Recall the measurements that you have learned in primary school. A physical quantity in science is defined as a physical characteristic that can be measured. The common base quantities used are length, mass, time, temperature and electric current (Table 1.2).
Table 1.2 Base quantities
Base quantity Length Mass Time Temperature Electric current
S.I. unit metre kilogram second kelvin ampere
The International System of Units, known as S.I. units (Système Internationale d’Unités) is used for the consistency of measurement. This allows accurate exchange of data and scientific knowledge to the entire world.
1.5
Symbol of S.I. unit m kg s K A
S.I. units have been used as the standard unit of physical quantities since 1960 to prevent problems of inconsistent units in measurement.
Aim: To identify physical quantities, values and S.I. units Instruction 1. Look at the objects in Photograph 1.10. State the S.I. unit that you can use to measure the physical quantity of each object. (a) (b) (c)
Length of table
Mass of onion
Temperature of water
Photograph 1.10 Objects
2. Observe the values and units that are used on the specification and labels of daily products. 3. Record your observation in your practical book. Value and unit Value and unit Photograph 1.11 Daily products Chapter 1
15
Prefixes can be used if the value of a physical quantity unit is too big or too small.
Table 1.3 The values of prefixes and symbols for physical quantity units
Prefix giga mega kilo deci centi milli micro nano
Value 1 000 000 000 1 000 000 1 000 0.1 0.01 0.001 0.000 001 0.000 000 001
Standard form 109 106 103 10–1 10–2 10–3 10–6 10–9
Symbol G M k d c m µ n
Prefix values are important and are used widely in calculations.
Converting Units of Base Quantity
a
Mass × 1000
kilogram (kg)
gram (g)
÷ 1000
b
Example: g 1. 1.9 kg = 1.9 kg = 1.9 × 1000 = 1900 g kg 2. 8200 g = 8200 g = 8200 ÷ 1000 = 8.2 kg
Length × 1000 kilometre (km)
× 10
metre (m) ÷ 1000
Example: 1. 80 m = 80 m = 80 × 100 = 8 000 cm
c
cm
× 10
decimetre (dm) ÷ 10
× 10
centimetre (cm) ÷ 10
Example: m 2. 600 cm = 600 cm = 600 ÷ 100 =6m
millimetre (mm) ÷ 10
Example: m 3. 95 mm = 95 mm = 95 ÷ 1000 = 0.095 m
Time × 60
× 60
hour (hr) minutes (min) second (s) ÷ 60 16
Bab 1 1 Chapter
÷ 60
Example: 1. 7 min = 7 min = 7 × 60 = 420 s
s
Example: hr 2. 450 s = 450 s = 450 ÷ 60 ÷ 60 = 0.125 hr
Chapter 1: Introduction to Scientific Investigation Pengenalan kepada Penyiasatan Saintifik
The Importance of S.I. units in Life Inconsistencies of units used in daily life may cause a lot of problems. For example, people in certain places may measure things by using pound and ounce, whereas people in other places may use grain and stone. The use of a standard unit for measurement will make it easier for scientists to communicate at international level. Problems shown in the situations below may arise if we do not use standard units.
Recall the measurements that you have learned in primary school such as span, fathom, pace and cubit. (a) Span
(b) Fathom
(c) Pace
(d) Cubit
Figure 1.8 Measurements in olden times
Situation 1 Zaidi and Hafiz, please measure the length of the classroom by counting your paces. Okay, teacher.
Situation 2
Syura, please go and buy three fathoms length of cloth for the curtain.
Okay, mother.
Uncle, I want to buy three fathoms of cloth to make a curtain. 40 paces
Teacher, why do we have different number of paces?
51 paces
They are different because the length of your paces are different.
Mother, why is the cloth so long?
Syura, your fathom is shorter because you are still a child.
Chapter Bab 1
17
1.6
21
ICS
Aim: To understand the implication of non-standardised units in our life Instruction 1. Work in groups. 2. Each group should gather information on the implication of non-standardised units in life. 3. Each group will present their discussion in class by using multimedia presentation such as PowerPoint.
1.3 1. List five physical quantities that you have studied. What is the S.I. unit and the symbol used for each of the quantities? 2. Convert the values below. cm (d) 24 000 g = kg (a) 0.13 m = kg (e) 0.006 A = mA (b) 18 000 mg = µm (c) 4 m =
1.4
The Use of Measuring Instruments, Accuracy, Consistency, Sensitivity and Errors
Let’s learn • Use the right measuring instrument and use it the right way to measure accurately and consistently the quantities of length, mass, time, temperature and electric current. • Use measuring instruments with higher accuracy and compare the measurements in terms of accuracy, consistency and sensitivity. • Explain how to minimise systematic errors and random errors. • Estimate the length, area, mass or volume of an object before taking actual measurements. • Explain with examples innovations of various types of measuring instruments through a multimedia presentation.
F
or the purpose of measurement, different measuring instruments are needed to collect data in an experiment. We need to ensure that we use the right measuring instruments to measure the quantities of length, mass, time, temperature and electric current accurately and consistently.
18
Chapter 1
Photograph 1.12 Measuring instruments
Accuracy – The ability of measuring instruments to obtain a value closest to the actual value. Consistency– The ability of measuring instruments to give the same readings with repeated measurements. Sensitivity – The ability of measuring instruments to detect a small change in the measurement quantity.
Chapter 1: Introduction to Scientific Investigation Pengenalan kepada Penyiasatan Saintifik
The Use of Right Measuring Instruments
a
Measuring Length Length is the distance between two points. The S.I. unit for length is metre (m). Length can also be measured in millimetres (mm), centimetres (cm) or kilometres (km).
One smallest scale value is equivalent to 1 mm or 0.1 cm.
Ruler
Measuring tape
Photograph 1.13 Instruments used to measure length
When using a ruler, the eyes of the observer must be parallel to the scale of the ruler to prevent parallax error (Figure 1.9). Parallax error occurs due to the wrong positioning of the eyes when taking measurements.
b
0 cm 1
3
4
5
6
7
Figure 1.9 How to prevent parallax error
Measuring Mass
The mass of an object is the quantity of matter in it. The S.I. unit for mass is kilogram (kg).
Lever balance
2
Triple beam balance
Photograph 1.14 Instruments used to measure mass
c
Measuring Time
The S.I. unit for time is second (s). stop button Other units include minute (min), hour (hr), day, month, year and decade.
Start, reset and
A stopwatch is used to measure time with an accuracy of 0.1 s or 0.2 s.
Example of a measuring instrument used in the olden times:
Figure 1.10 A weighing scale
Ring
Photograph 1.15 A stopwatch Chapter 1 19
d
Measuring Temperature
Temperature is the degree of heat of an object. The S.I. unit for temperature is kelvin (K). However, degree Celsius (°C) is usually used as a measuring unit for temperature.
Science Exploration To convert from degree Celsius to Kelvin, you have to add 273 to the temperature in degree Celsius. 0°C + 273 = 273 K
Laboratory thermometer
A laboratory thermometer can be used to measure temperature with an accuracy of 10C.
A clinical thermometer can be used to measure temperature with an accuracy of 0.10C.
Clinical thermometer
Photograph 1.16 Instruments used to measure temperature
e
Measuring Electric Current
An ammeter is used to measure electric current in a circuit.
Ammeter
Photograph 1.17 An ammeter Systematic error (zero error) 1 0
2
1
3
A
4
Positive zero error
0
2
A
Random error (parallax error) 3 4
Negative zero error
Zero adjustment button
Figure 1.11 Systematic error and random error 20
Chapter 1
Antiparallax mirror to prevent parallax error
Chapter 1: Introduction to Scientific Investigation Pengenalan kepada Penyiasatan Saintifik
f
Measuring Volume of Water
20
A measuring cylinder can be used to measure the volume of water.
11 ml 12 ml
10
13 ml
Parallax error occurs when the reader’s eyes are not perpendicular to the reading scale.
The right way to take a reading Measuring cylinder
Figure 1.12 The instrument used to measure the volume of water
1.7 Aim: To use and handle measuring instruments correctly Materials and apparatus: Ruler, measuring tape, thermometer, stopwatch, triple beam balance, ammeter, measuring cylinder, book, beaker, water. Instruction 1. Work in groups. 2. Each group has to carry out measurements at five stations by using the right measuring instruments. (a) Station 1: Measure the thickness of the Form 1 Science textbook and length of the whiteboard. (b) Station 2: Measure the volume and temperature of water. (c) Station 3: Measure the time taken to walk from one end to the other end of the laboratory. (d) Station 4: Measure the mass of a beaker, a book and other objects given. (e) Station 5: Measure the electric current in a circuit. 3. Each station will have a piece of paper to record the measurements. 4. Each group is required to take three readings at each station to obtain an accurate value and calculate the average reading as shown in the table below. Then, state the relationship between the smallest scale value on the measuring instrument with the accuracy of the reading. Measuring instrument
Reading 1
Reading 2
Reading 3
Average
The smallest scale value: 5. The time allocated for each station is 10 minutes. 6. Each group will be placed at one station. A bell will be rung once to start the activity and twice for the groups to move to the next station. 7. Discuss the findings gathered in your group. Chapter 1
21
Using Measuring Instruments with Higher Accuracy
a
Measuring Length
Vernier Calipers Vernier calipers is used to measure the thickness or outer diameter, inner diameter and depth of an object. The smallest division of the reading of a vernier calipers is 0.01 cm or 0.1 mm. Therefore, vernier calipers is much more accurate compared to a ruler which can only measure the smallest reading up to 0.1 cm or 1 mm. Main scale
3.2 cm
3 0 cm
1
2
3
Skala utama
4
5
4
6
0 5 10
0 5 10
Main scale
Vernier scale
The vernier scale coincides with the main scale at 0.02 cm
Vernier scale
Reading = 3.20 + 0.02 = 3.22 cm
Figure 1.13 Measurement of a round object by using vernier calipers
Systematic errors are caused by using measuring instruments that are not accurate. For example, zero error that occurs on the measuring instruments, the error of the person who takes the measurement or environmental factors. Zero error can be determined when the jaws of the vernier calipers are closed.
0
1
0
0
1
0
0 5 10
0 5 10
3rd line. Read from the “0” mark on the vernier scale
No zero error
5 10 6th line. Read from the “10” mark on the vernier scale
Positive zero error
Negative zero error
+ 0.03 cm
– 0.06 cm
Figure 1.14 Zero errors in vernier calipers
1
To determine the positive zero error, the error has to be read from the “0” mark on the vernier scale. To determine the negative zero error, the error has to be read from the “10” mark on the vernier scale.
To obtain the actual reading, zero error has to be taken into consideration. Actual reading = Reading of vernier calipers – zero error
22
Chapter 1
Chapter 1: Introduction to Scientific Investigation Pengenalan kepada Penyiasatan Saintifik
Micrometer Screw Gauge
Anvil
Spindle Vernier scale
A micrometer screw gauge is used to measure the thickness and diameter of small objects like paper and hair. The smallest division of the micrometer screw gauge’s reading is 0.001 cm or 0.01 mm. Therefore, the micrometer screw gauge is more accurate than the vernier calipers.
Main scale
Photograph 1.18 A micrometer screw gauge
The vernier scale has 50 divisions. Each division on the vernier scale is 0.01 mm.
Vernier scale
45 40
Main scale
0
1
2
The eyes of the reader should be perpendicular to the reading to prevent parallax error.
3
0.38 mm
35 34
3.50 mm
Reading of micrometer screw gauge = 3.50 + 0.38 = 3.88 mm
Figure 1.15 Reading of micrometer screw gauge
0
0
Figure 1.16 The right way to take a reading
Zero error of the micrometer screw gauge can be determined when the anvil is closed completely. 0
0
0
No zero error
0
0
Positive zero error (+ 0.01 mm)
0 45
Negative zero error (– 0.02 mm)
Figure 1.17 Zero error of the micrometer screw gauge
To get the actual reading from a micrometer screw gauge, zero error has to be taken into consideration. Actual reading = Reading of micrometer screw gauge – zero error Chapter 1
23
Digital vernier calipers and digital micrometer screw gauge can measure measurements with more accuracy and precision.
Digital vernier calipers
b
Digital micrometer screw gauge
Photograph 1.19 A digital vernier calipers and a digital micrometer screw gauge
Measuring Mass
A digital electronic balance can read measurement of mass more accurately and precisely.
Photograph 1.20 A digital electronic balance
c
Measuring Time A digital stopwatch is more accurate than a normal stopwatch because it can measure time accurately up to 0.01 second whereas the normal stopwatch can only measure up to 0.1 second. Photograph 1.21 A digital stopwatch
d
Measuring Temperature
Photograph 1.22 A digital thermometer
e
A digital thermometer can give temperature readings more accurately and precisely because it can measure temperature with an accuracy up to 0.1°C. Therefore, digital thermometers are widely used in clinics nowadays.
Measuring Electric Current
A digital ammeter gives more accurate and precise readings because this instrument can measure electric current with an accuracy up to 0.01A. Digital ammeter
Photograph 1.23 A digital ammeter 24
Chapter 1
Chapter 1: Introduction to Scientific Investigation Pengenalan kepada Penyiasatan Saintifik
1.8 Aim: To measure, use and handle instruments with higher accuracy correctly Materials and apparatus: Vernier calipers, micrometer screw gauge, digital electronic balance, digital ammeter, digital thermometer, clinical thermometer. Instruction 1. Work in groups. 2. Each group has to conduct the following measuring activities by using higher accuracy instruments. (a) Measure the thickness of the Form 1 Science textbook using the vernier calipers and micrometer screw gauge (b) Measure the mass of the Form 1 Science textbook using a digital electronic balance (c) Measure the electric current of a circuit using a digital ammeter (d) Measure the body temperature with a clinical thermometer and a digital thermometer 3. Each group has to take three readings in order to obtain an accurate reading. State the average reading taken in the table below. Then, relate the smallest scale value on the measuring instrument to the accuracy of the reading. Measuring instrument
Reading 1
Reading 2
Reading 3
Average
The smallest scale value: 4. Each group has to compare their readings obtained from Activity 1.7 with the reading obtained from this activity in terms of accuracy, consistency and sensitivity in the table below. Then, relate the smallest scale value on the measuring instrument to the sensitivity of reading. Make sure the units are recorded. Measurement Thickness of book Mass of book Electric current Body temperature
Measuring Average Accuracy Consistency Sensitivity instrument reading Ruler Vernier calipers Micrometer screw gauge Triple beam balance Digital electronic balance Ammeter Digital ammeter Clinical thermometer Digital thermometer
5. Present your findings in class. Questions 1. Based on your findings, which measuring instrument is the most sensitive – ruler, vernier calipers or micrometer screw gauge? 2. Between the triple beam balance and digital electronic balance, which instrument can give a more precise and accurate reading? Chapter 1
25
How to Minimise Systematic Errors and Random Errors Errors Systematic errors
Random errors
Consistent errors obtained from a measuring instrument for every measurement. Examples: • Zero error • Inaccurate measuring instrument
The uncertainties in measurement caused by the observer when taking measurements. Examples: • Parallax error • Carelessness of observer when taking the reading • Wrong technique
Ways to overcome: • Conduct experiments with caution • Repeat the experiment using different measuring instruments
Ways to overcome: • Take a few readings of measurement and take the average reading • To reduce the impact of parallax errors, observer’s eyes should be perpendicular to the scale reading
Making an Estimation before Taking the Actual Measurement When a proper measuring instrument is not available during an experiment, the best way is to make an estimation beforehand. Later, a precise and accurate measuring instrument will be used.
a
Estimating Length
1.9
Aim: To make a link between making estimation and taking the actual measurement Materials and Apparatus: Pencil and ruler Instruction 1. Measure the length of a pencil (p cm). 2. Measure and record the length of a table using the pencil. Length of table = number of pencil × p cm. 3. Measure and record the length of the table using a ruler.
Figure 1.18 Estimating the length of a table
Question What is the difference between the length of the table measured using a pencil (estimated measurement) and the length of the table measured using a ruler (actual measurement)? 26
Chapter 1
Chapter 1: Introduction to Scientific Investigation Pengenalan kepada Penyiasatan Saintifik
b
Estimating Area Area is the size of a surface. The S.I. unit for area is m2. For objects with regular shapes, area can be measured by using formulae. For example, the area of a square is length × width. What is the formula of the area of other objects as shown in Figure 1.19?
For objects with irregular shapes, area can be estimated by using the graph paper method.
Figure 1.19 Objects with regular shapes
Example:
✔
✔
✔
✔
✔
✔
✔ ✔
✔
✔
✔ ✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
Mark ‘✔’ on squares that are half and more than half covered by the leaf. Count the total number of squares marked ‘✔’ and record your result. The area of the shape = 23 cm2
1 cm
1 cm
Figure 1.20 Estimating the area of a leaf
72
Estimating Mass What is the mass of a sheet of paper which is light and cannot be measured? If the mass of 100 sheets of paper is 500 g, the mass of 1 sheet of paper is estimated at 5 g.
d
8
1 3
c
0
4 56
g 40
24
2
Mass of 100 sheets of paper = 500 g
Figure 1.21 The mass of 100 sheets of paper
Estimating Volume The volume of an object with a regular shape can be calculated by using formula, whereas the volume of objects with irregular shapes can be estimated by using the water displacement method.
4 cm
4 cm
4 cm
Volume = height × width × length =4×4×4 = 64 cm3 Object with regular shape
23 cm3 15 cm
3
Initial volume Object with irregular shape
Stone Final volume Volume of the stone = 23 cm3 – 15 cm3 = 8 cm3
Figure 1.22 Calculating volume Chapter 1
27
1.4 1. What is the reading of the micrometer screw gauge below? (b) (a) 10 0
5
30
0
25
5
2. Estimate the area of the drawing if every square represents an area of 1 cm × 1 cm or 1 cm2. 3. Chong is standing on a weighing balance. The value shown is 55 kg. What is the meaning of the value?
Technology and Innovation in Measuring Instruments Measuring blood pressure is made easier by using the digital blood pressure monitor (Photograph 1.24). Patients who have blood pressure problems can obtain precise and reliable blood pressure reading within a few seconds. Can you give examples of other types of innovation in measuring instruments? Photograph 1.24 A digital blood pressure measuring instrument
1.5
Density
Let’s learn • • • • • •
Arrange materials sequentially based on their density. Predict whether the materials will float or sink according to their density. Define the operational definition of density. Calculate density using the formula (density = mass / volume) and water displacement method. Explain the phenomena related to density differences in everyday life. Innovate objects, food or beverage using the concept of density.
Look at the picture. Why do people float on the Dead Sea easily? This is because the Dead Sea has an extremely high salt content. This makes the waters of the Dead Sea higher in density compared to other seas. What is density? Density of a material is the mass per unit volume of the material. Photograph 1.25 The density of water in the Dead Sea is extremely high and can make people float easily 28
Chapter 1
Chapter 1: Introduction to Scientific Investigation Pengenalan kepada Penyiasatan Saintifik
The formula of density is as below: Density (g cm–3) =
Mass (g) Volume (cm3)
A triangle can be used for the formula that relates density, mass and volume.
Mass Density
Volume
1.10 Aim : To investigate the relationship between the mass and density of various solids that have the same volume Materials and apparatus: Copper cube, iron cube, cork cube and wooden cube that have the volume of 1 cm3 each, water, basin, weighing balance. Instruction 1. You are given four cubes that have the same volume as shown below.
Copper
Iron
Cork
Wood
Figure 1.23 Four cubes that have the same volume
2. Weigh the mass of each cube and calculate the density of each cube using the formula: Density (g cm–3) =
Mass (g) Volume (cm3)
3. Record the value of mass and density in the table below. Volume (cm3)
Copper
Iron
Cork
Wood
1
1
1
1
Mass (g)
Density (g cm–3)
4. Put the cubes into a basin of water. Observe whether they float or sink. Questions 1. What is the relationship between mass and density if the volume of all the four solids is the same? 2. Arrange the above solids according to their density in an ascending order. 3. Based on the observation from step 4, state the operational definition of density. Chapter 1
29
Recall the information that you have learned in primary school. Materials that are less dense will float and will be above the materials which are denser whereas materials which are denser will sink and will be under the materials which are less dense (Figure 1.24). For example, ice will float on water surface and stones will sink to the bottom. Table 1.4 Density of various materials
Material Gold Lead Copper Aluminium Ice Cork Mercury Seawater Pure water (at 40°C) Petrol
Density (g cm–3) 19.30 11.30 8.92 2.70 0.92 0.24 13.60 1.03 1.00 0.80
Petrol (0.80 g cm−3) Water (1.00 g cm−3) Mercury (13.60 g cm−3)
Cork (0.24 g cm−3) Water (1.00 g cm−3) Copper (8.92 g cm−3)
Figure 1.24 Materials which are less dense than water will float whereas materials which are more dense than water will sink
From the table above, the arrangement of the materials in an ascending order based on density is cork, petrol, ice, water, copper and mercury.
Cork Petrol Ice Water Copper
B
Predict what will happen if both objects are put into a pail of tap water? How can you float the two objects?
Mercury
Figure 1.25 Arrangement of materials in the measuring cylinder
Photograph 1.26 Objects
Calculation of Density by Using Formula Example: The mass of a measuring cylinder is 230 g. After 50 cm3 of liquid X is poured into it, the mass of the measuring cylinder and liquid X becomes 320 g. What is the density of liquid X?
30
Chapter 1
Solution: Mass of liquid X = 320 g – 230 g = 90 g Mass (g) Density (g c m–3) = Volume (cm3) 90 g = 50 cm3 = 1.8 g c m–3
Chapter 1: Introduction to Scientific Investigation Pengenalan kepada Penyiasatan Saintifik
Determining the Density of Objects Using the Water Displacement Method The density of irregular objects can be determined by using water displacement method. What is water displacement method?
Water displacement method is a method that is used to measure the volume of an irregular objects. Let us carry out the activity below to determine density using the water displacement method.
Figure 1.26 Archimedes The water displacement method was discovered by a Greek scientist named Archimedes.
1.11 Aim: To determine the volume of objects using the water displacement method Materials and apparatus: Stone, thread, 100 ml measuring cylinder, weighing balance, water. Instruction 1. Weigh and record the reading of the mass of a stone. 2. Pour 50 ml water into a 100 ml measuring cylinder. Take the initial reading of the volume of water. 3. Tie the stone with a piece of thread. 4. Lower the stone slowly into the measuring cylinder until the stone is immersed in the water (Figure 1.27).
Initial reading
50 ml
Final reading Stone
1 ml = 1 cm3
Figure 1.27
5. Read the new water level (final reading of volume). Next, determine and record the volume of the stone in cm3. 6. Calculate the density of the stone. Results g Mass of stone = Initial reading of volume: cm3 Final reading of volume: cm3 Volume of stone = Final reading of volume – Initial reading of volume Mass Density = Volume Question What is the density of the stone? Chapter 1
31
Differences in Density in Everyday Life There are many phenomena related to differences in density in everyday life.
Ice is less dense than water, so ice floats on the surface.
Balloons that contain helium gas float in the air because helium gas is less dense than air.
Timber can be transported by water because timber is less dense than water.
Photograph 1.27 Phenomena related to the differences in density in everyday life
1.12
21
ICS
Aim: To investigate the phenomena related to the differences in density in our everyday life Instruction 1. Work in groups. 2. Gather information about phenomena related to density in everyday life and discuss. 3. Present the discussion of your group using multimedia presentation.
Innovation of Objects, Food or Drinks Using the Concept of Density Look at Photograph 1.28. Nowadays, restaurant operators are very creative in preparing various types of food and drinks using the concept of differences in density. Use your creativity to create interesting objects, food or drinks for sale. 21
ISS
Threelayered tea Layered juice
Photograph 1.28 Innovation of food and drinks 32
Chapter 1
Chapter 1: Introduction to Scientific Investigation Pengenalan kepada Penyiasatan Saintifik
1.5 1. Determine the density of the samples in the diagram below. A B C 4 cm 5 cm
5 cm Mass of sample A = 200 g
5 cm
2 cm 5 cm
Mass of sample B = 100 g
ml 200
1 cm 5 cm
5 cm
Mass of sample C = 50 g
2. Three types of liquid which do not mix, P, Q and R are poured together in a measuring cylinder as shown in the diagram. Which liquid is the most dense? Why?
1.6
150
P
100
Q
50
R
Steps in a Scientific Investigation
Let’s learn • Differentiate each science process skill. • Make a sequence on the steps of carrying out a scientific investigation in the correct order. • Conduct a scientific investigation to solve a simple problem.
Recall the science process skills that you have learned in primary school. There are twelve important science process skills in a scientific investigation. Can you differentiate each skill? Observing
Classifying
Predicting
Communicating
Defining operationally
Controlling variables
Measuring and using numbers
Using time-space relationships Making a hypothesis
Making inferences
Interpreting data
Experimenting
1.13 Aim: To differentiate each science process skill Instruction 1. Work in groups. Each group will be given one station with a science process skill. 2. Each group has to look for information about the science process skill and present their findings in class.
Chapter 1
33
Scientific Method Scientific method is a systematic method used to solve problems in science. This method consists of a few important steps to enable a problem to be solved or explained using the correct method.
1
Identify a problem – Identify a problem that could be tested with a scientific investigation.
2
Construct a hypothesis – We need to build a hypothesis as an initial explanation of the observation or phenomenon being investigated. The hypothesis has to be tested.
3
Control variables – Identify the type of variables involved. Variables are physical quantities that influence the observation or scientific phenomena and it consists of manipulated variables, constant variables and responding variables.
4
Plan an experiment – We have to design an experiment carefully beforehand. We also need to choose the right materials and apparatus for the experiment.
5
Conduct the experiment – While conducting the experiment, precautions must be practised at all times to obtain a more accurate data. Safety measures must also be followed to prevent accidents. Let’s test your hypothesis.
34
Chapter 1
Oops, I spilled the water! What can I use to absorb the water quickly?
Cloth towel absorbs water more quickly than tissue paper.
Chapter 1: Introduction to Scientific Investigation Pengenalan kepada Penyiasatan Saintifik
6
Collect data – Data collection is carried out carefully using suitable instruments while taking into consideration any random or systematic error that might occur. Make sure the measurements are carried out at least three times to obtain a more accurate and precise reading. Use a table to record your data.
7
Analyse and interpret data – Analysis must be accompanied by effective communication forms such as graphs and tables. Graphs and tables assist us to easily interpret the data.
The amount of water absorbed (cm3)
We need to carry out the measurement at least 3 times to get an accurate reading.
25 20 15 10 5 0
Tissue paper
Cloth
Types of towels
Figure 1.28 The amount of water absorbed against types of towels
8
Make a conclusion – Conclusions are made based on experimental analysis; either hypothesis is accepted or rejected. If rejected, we need to make a new hypothesis and carry out the experiment again.
9
Write a report – When writing a report, all important data and information must be included. Problem statement: Hypothesis: Aim: Variables: Materials and Apparatus: Procedure: Observation/results: Analysis and interpretation of data: Conclusion: Chapter 1
35
Example of a Complete Experiment Report
Experiment 11. Identify the problem
22. Construct a hypothesis
1.1
Problem Statement: How does the length of a pendulum influence the period of one complete oscillation? Hypothesis: The longer the length of a pendulum, the longer the period taken for one complete oscillation. Aim: To investigate the relationship between the length of a pendulum and the period of oscillation Wood Length of pendulum Pendulum
33. Control variables
44. Plan and conduct the experiment
Note Students have to write procedure in the passive form.
55. Present the data collected
A
B
One complete oscillation A B A
Figure 1.29 Set-up of apparatus
Manipulated variable: Length of pendulum Responding variable: Time taken for 10 complete oscillations Constant variable: Mass of pendulum, angle of oscillation Materials and apparatus: Wood, retort stand with clamp, pendulum, string, stopwatch, metre ruler. Procedure 1. A pendulum with a length of 20 cm is used. 2. The pendulum is pulled to one side and then released to make 10 complete oscillations. 3. The time taken for 10 complete oscillations is recorded. 4. The experiment is repeated using different lengths of pendulum. Results Length of Time taken for 10 complete oscillations (s) pendulum (cm) Reading 1 Reading 2 Reading 3 Average 20 9.1 9.2 9.0 9.1 30 11.3 11.4 11.4 11.4 40 13.1 13.0 13.1 13.1 50 14.4 14.3 14.3 14.3 60 15.2 15.1 15.3 15.2
66. Interpret data and
results with scientific reasoning
36
Chapter 1
Time taken for 10 complete oscillations (s)
Discussion The longer the length of the pendulum, the longer the time taken for 10 complete oscillations.
20 15 10 5 0
10 20 30 40 50 60 Length of pendulum (cm)
Figure 1.30 Graph
Chapter 1: Introduction to Scientific Investigation Pengenalan kepada Penyiasatan Saintifik
77. Make a conclusion
Conclusion: Hypothesis is accepted. The longer the length of the pendulum, the longer the time taken for 10 complete oscillations.
1.6 1. What is an inference? 2. State the manipulated, responding and constant variables when conducting an experiment regarding water evaporation from containers with different surface area.
1.7
Scientific Attitudes and Values in Carrying Out Scientific Investigations
Let’s learn • Support the scientific attitudes and values practised by scientists. • Justify the need to practise scientific attitudes and values when carrying out an investigation. • Practise scientific attitudes and values while carrying out a scientific investigation.
What are the scientific approach and values that must be practised by a scientist? 21
Students must have positive attitudes and values while conducting investigations.
ISS
Scientific attitudes that should be practised Be interested and curious about surroundings
Be honest and accurate while recording and validating data
Be responsible for your own and others safety as well as for the environment.
Figure 1.31 Scientific attitudes and moral values
Examples of other values that need to be practised during a scientific investigation: 1. Realise that scientific knowledge is one way to understand our environment Example of other values that need to be practised during a scientific investigation: 2. Appreciate and practise a clean and healthy lifestyle 3. Appreciate the balance in the natural environment 4. Be polite and respect each other 5. Be grateful that the natural environment is a gift from God Chapter 1
37
Science in Life
The purpose is to get more accurate results, to be an effective decision maker, willing to change and adapt to new ideas.
Why do we need to practise scientific attitudes and values during a scientific investigation?
Besides, we can also become good problem solvers and responsible and creative researchers.
1.7 1. Conclusions of a scientific investigation can be influenced by scientific attitudes and values practised when carrying out experiments. What are the scientific attitudes and values that need to be practised by a student to make accurate conclusions? 2. What are the attitudes that will assist scientists to understand the haze phenomenon that causes air pollution?
My Malaysia The National Science Centre (Pusat Sains Negara) was built to create a generation of scientists. Students can learn new things when visiting the centre. There are exhibitions about the earth’s ecosystem, the history of science and much more.
National Science Centre http://www.psn.gov.my
38
Chapter 1
Photograph 1.29 National Science Centre
Innovation in technology in everyday life
Subjects to be studied
Careers related to science
The field of science
The importance of science in everyday life
The meaning of science
Relate daily activities to science
Science is part of daily life
The rules and safety measures in the laboratory
Symbols and examples
Hazardous materials
Functions of the apparatus
Apparatus
Science laboratory
Steps in a scientific investigation
The importance of the use of S.I. units in daily life
Symbol and values of prefixes
Base quantities
Physical quantities and their units
Science
Examples of innovations of various types of measuring instruments
Estimating length, area, mass or volume of an object before taking actual measurement
The ways to minimise systematic errors and random errors
Use measuring instruments with higher accuracy
Use the right measuring instrument
The use of measuring instruments
The use of measuring instruments
Scientific attitudes and values
Innovate objects, food or drinks using the concept of density
Phenomena related to difference in density in everyday life
Arrange materials sequentially based on density
Density
Chapter 1: Introduction to Scientific Investigation Pengenalan kepada Penyiasatan Saintifik
Chapter 1
39
After learning this chapter, you are able to: 1.1 Science is Part of Daily Life Relate daily activities to science. Generalise the meaning of science. Summarise the importance of science in everyday life. Describe the fields of science. Communicate about careers related to science. Relate subjects to be studied in science to careers of interest. Describe innovation in technology. 1.2 Your Science Laboratory Identify and state functions of apparatus. Identify symbols and examples of hazardous materials in the laboratory. Draw and label apparatus commonly used in the laboratory and classify based on how it is used. Justify the regulations and safety measures in the laboratory. 1.3 Physical Quantities and Their Units Identify and use the correct units for different physical quantities. Identify the symbols and values of prefixes used in measurement. Convert base quantity units for mass, length and time such as grams to kilograms, centimetres to metres, seconds to hours and vice versa. Justify the importance of the use of S.I. units in daily life. 1.4 The Use of Measuring Instruments, Accuracy, Consistency, Sensitivity and Errors Use the right measuring instrument and use it in the right way. Use measuring instruments with higher accuracy. Explain how to minimise systematic errors and random errors. Estimate the length, area, mass or volume of an object before taking actual measurements. Explain with examples innovations of various types of measuring instruments through a multimedia presentation. 1.5 Density Arrange materials sequentially based on their density. Predict whether the materials will float or sink according to their density. Define operational definition of density. Calculate density using the formula (density = mass / volume) and water displacement method. Explain the phenomena related to density difference in everyday life. Innovate objects, food or beverage using the concept of density. 1.6 Steps in a Scientific Investigation Differentiate each science process skill. 40
Chapter 1
Chapter 1: Introduction to Scientific Investigation Pengenalan kepada Penyiasatan Saintifik
Make a sequence on the steps of carrying out a scientific investigation in the correct order. Conduct a scientific investigation to solve a simple problem. 1.7 Scientific Attitudes and Values in Carrying Out Scientific Investigations Support scientific attitudes and values practised by scientists. Justify the need to practice scientific attitudes and values when carrying out an investigation. Practise scientific attitudes and values while carrying out a scientific investigation.
Summative Practice
1
1. Figure 1 shows a chemical bottle with a hazard symbol. Mark (✔) at the correct hazard symbol.
Radioactive material
Explosive material
Corrosive material
Highly flammable material Figure 1
2. P, Q, R, S, T, U, V and W are steps to carry out scientific investigations based on inquiry. Arrange the steps according to the correct sequence.
P Q R S
– – – –
Control variables Conduct the experiment Construct a hypothesis Make a conclusion
T – U – V – W –
Plan the experiment Analyse and interpret data Identify the problem Collect data
3. Convert 100 g to kg. 100 g = 4. Name the measuring instruments below. (a)
(b) 0 cm
1 0
2
3
4
5
6
7
8
9
10
5 10
Figure 2
5. Azman is asked by his teacher to heat alcohol in a test tube. What are the steps that need to be taken while handling alcohol? How should these steps be taken? Explain. Chapter 1
41
6. A biologist is investigating a butterfly. One of the required information is the area of both wings of the butterfly. If every square on the graph paper represents a scale of 1 cm × 1 cm, calculate the area of the wings. Figure 3 Rate of evaporation (cm3 s−1)
7. Wendy conducted an experiment to study the relationship between surface area and the rate of evaporation. The results were plotted in a graph form. Based on the graph, what is the conclusion that could be made?
Surface area (cm2)
Figure 4
8. Henry was given three measuring instruments, P, Q and R. Which one of these could be used to measure the thickness of a piece of wire accurately and precisely? Why? 0
0 cm
1
2 0
3
4
5
6
7
8
9
5
20 15 10
0 cm
1
5
10
5 10
P
2
3
4
5
6
7
8
9
10
11
12
13
14
15
R
Q
Figure 5
9. During an experiment, a chemical reaction caused a small explosion which resulted in light injury to Aisyah. Dina happened to be at her side during the incident. What action should Dina have taken? 10. Aziema observed that clothes that were hung outside the house dried faster than the clothes that were hung inside the house. Construct a hypothesis.
11. Punita observed that the plant in pot C grew healthier than the plants in pot A and B. Construct a hypothesis and plan an experiment to test the hypothesis. Pot A: Watered once every three days Pot B: Watered once a week Pot C: Watered everyday
Pot A
Pot B
Pot C
Figure 6
12. Pak Wan wants to sell a type of drink that has many layers to attract his customers. Create a drink and explain the methods to produce the drink. 42
Chapter 1
Sel Sebagai Chapter 2: Cell Unit asAsas the Basic Hidupan Unit Saintifik of Life Pengenalan kepada Penyiasatan
2
Maintenance and Continuity of Life
esis? tosynth ll? o e h c p t is u t arry o Wha plants c is? o d y h gs? tas W homeos roduce offsprin orm? is t a h W nts f ans p do hum and fruits of pla How s do seed How
Chapter Bab 2
43
Chapter
2
Cell as the Basic Unit of Life What is the basic unit of life? What is a cell?
Let’s study: Cell – Structure, Function and Organisation Cell Respiration and Photosynthesis 44
Chapter 2
Sel Sebagai Chapter 2: Cell Unit asAsas the Basic Hidupan Unit Saintifik of Life Pengenalan kepada Penyiasatan
SCIENCE BULLETIN
ORIGINS OF CELL
Robert Hooke ed for the first time by rv se ob s wa ll ce e pl sim ported his oscope in 1665. He re icr m al tic op n ow s mans using hi ia. Before this, the Ro ph ra og icr M , ok bo s observations in hi ed bigger when ed that objects appear rv se ob y ur nt ce st fir observed in the n Leeuwenhoek also va e ni to An s. as gl h 74. seen throug for the first time in 16 ter wa of op dr a in s microorganism
A
Cell Unicellular organisms Multicellular organisms Microscope Nucleus Cytoplasm Chloroplast
Palisade cell Epidermis cell Tissue Organ System Organism Cell respiration Photosynthesis Chapter Bab 2
45
2.1
Cell - Structure, Function and Organisation
Let’s learn • Explain that living things are made up of cells that carry out life’s functions and undergo cell division. • Demonstrate the preparation of slides of animal cells and plant cells using the correct procedures. • Communicate about each structure in cells with their functions as well as compare and contrast animal cells with plant cells. • Explain with examples the characteristics of unicellular and multicellular organisms for animal cells and plant cells. • Differentiate the types and functions of animal cells and plant cells. • Conceptualise the formation of a plant and an animal with reference to the sequence of cell organisation: Cell → tissue → organ → system → organism • Appreciate and be amazed by the existence of various organisms.
What is a Cell? This house is built of bricks. Each brick is the basic unit of the house. The same applies to living things. Living things are composed of basic units called cells.
Oh, our bodies are made up of cells. Who was the first person to discover the cell?
In 1665, an English scientist named Robert Hooke invented a simple microscope to observe a piece of cork. He saw lots of small box-shaped structures within the cork. Therefore, he named the structures as cells.
Photograph 2.1 A house built of bricks
Robert Hooke
Photograph 2.2 Cork cells observed by Robert Hooke In 1674, Antonie van Leeuwenhoek invented a powerful microscope. He observed moving microorganisms in a drop of rain water using his microscope.
46
Chapter 2
Sel Sebagai Chapter 2: Cell Unit asAsas the Basic Hidupan Unit Saintifik of Life Pengenalan kepada Penyiasatan
Cells carry out all life’s functions such as growth, respiration, reproduction and excretion. A cell resembles a microscopic factory where thousands of chemical reactions occur.
What will happen if the cells in our bodies are old or damaged? Figure 2.1 A cell resembles a microscropic factory
Cells undergo division process to form new cells and replace damaged cells. One individual cell becomes two cells and so on. Scan the picture below to see a video on cell division.
Video on cell division
Division of a cell Photograph 2.3 Process of division of a cell
Science Exploration In controlled conditions, cells divide normally. Cancer occurs when normal cells divide continuously without control. Figure 2.2 shows three stages of cancerous cell development. What is the main cause of cancer? How can cancer be detected? Discuss. Cancer Cancer cell
Tumour Skin cell
The formation of cancer www.cancercenter.com/ what-is-cancer/
Blood vessel
Figure 2.2 Stages of cancerous cell development Chapter Bab 2
47
The Structure of Animal Cells and Plant Cells How does the structure of animal cells and plant cells look like? Let us carry out the activity below.
2.1 Aim: To investigate the structure of animal cells using cheek cells Materials and apparatus: Glass slide, cover glass, microscope, toothpick, mounting needle, methylene blue solution, filter paper, dropper. Instruction 1. Put a drop of distilled water onto a glass slide. 2. Scrape the inside of your cheek using a toothpick (Figure 2.3). 3. Place the cells onto the glass slide. 4. Add a drop of methylene blue solution on the cells. 5. Gently close the cells with a cover glass using a mounting Figure 2.3 Scrape the needle to make sure no air bubbles get trapped. inside of the cheek 6. Use a filter paper to absorb any excess methylene blue solution. 7. Observe the glass slide under a microscope using low power Note objective lens, followed by high power lens. Methylene blue solution 8. Draw and label the structure of the cheek cells observed in is used to dye the cells your practical book. observed under a microscope.
a
c
b Toothpick A drop of distilled water
Put distilled water
Add a drop of methylene blue solution Distilled water and cheek cells
Place cheek cells onto the glass slide.
f
e
d Filter paper
Glass slide Observe the cells
Absorb excess methylene blue solution
Figure 2.4 Preparing a cheek cell slide
48
Bab 2 2 Chapter
Mounting needle
Cover glass
Lower the cover glass slowly
Sel Sebagai Chapter 2: Cell Unit asAsas the Basic Hidupan Unit Saintifik of Life Pengenalan kepada Penyiasatan
2.2 Aim: To investigate the structure of plant cells using onion cells Materials and apparatus: Glass slide, cover glass, microscope, knife, mounting needle, dropper, iodine solution, onion, filter paper, forceps. Instruction a
b Knife Add distilled water
h
c
Epidermis of onion
Distilled water
f
Filter paper Glass slide
e Iodine solution
Cover glass Mounting needle 45°
Observe the specimen
Forceps Epidermis of onion
Onion leaf’s scale
g
d
Distilled water and epidermis of onion
Figure 2.5 Preparing an onion cell slide
1. Peel a layer of epidermis from an onion bulb using a knife. 2. Place the epidermis layer onto a glass slide. 3. Add a drop of iodine solution onto the epidermis layer. Be careful when using 4. Gently place a cover glass on the epidermis layer using a a knife. mounting needle to make sure no air bubbles get trapped. 5. Use a filter paper to absorb any excess iodine solution. 6. Observe the slide under a microscope using low power objective lens, followed by high power lens. 7. Draw and label the structure of onion cells in your practical book.
From Activity 2.1 and 2.2, the structure of plant cells and animal cells are shown as in the picture below.
Onion cells
Cheek cells
Photograph 2.4 Onion cells and cheek cells Chapter Bab 2
49
Functions of Structures in Animal Cells and Plant Cells What is the function of each structure?
Chloroplast • Absorbs light energy for the process of photosynthesis.
Cell membrane • Controls the flow of materials in and out of the cell.
Mitochondria • Produces energy for reactions.
Nucleus • Controls all activities in the cell. • Contains chromosomes consisting of deoxyribonucleic acid (DNA) that carries genetic information.
Vacuole • Provides support to cells when filled with cell sap. Plant cell
Cell wall • Provides support, protection and fixed shape to the cell.
Cytoplasm • Acts as a medium where chemical reactions occur.
Figure 2.6 The function of structures in a plant cell 50
Bab 2 2 Chapter
Sel Sebagai Chapter 2: Cell Unit asAsas the Basic Hidupan Unit Saintifik of Life Pengenalan kepada Penyiasatan
Cell membrane • Controls the flow of materials in and out of the cell.
Mitochondria • Produces energy for reactions.
Nucleus • Controls all activities in the cell. • Contains chromosomes consisting of deoxyribonucleic acid (DNA) that carries genetic information.
Animal cell Cytoplasm • Acts as a medium where chemical reactions occur.
Figure 2.7 The function of structures in an animal cell Chapter Bab 2
51
52
Bab 2 2 Chapter
There are also animal cells containing small vacuoles whose contents are different from the vacuole in plants cells.
Notes
No vacuole
No chloroplast
Mitochondria
Cytoplasm
Cell membrane
Nucleus
Has fixed shape
Plant cell
Has cell wall
Figure 2.8 The similarities and differences between animal cells and plant cells
No fixed shape
Animal cell
No cell wall
The double bubble map below shows the similarities and differences between animal cells and plant cells.
Comparison between Animal Cells and Plant Cells
Has vacuole
Has chloroplast
Sel Sebagai Chapter 2: Cell Unit asAsas the Basic Hidupan Unit Saintifik of Life Pengenalan kepada Penyiasatan
Unicellular and Multicellular Organisms Unicellular organisms (“uni” means one) are organisms that consist of only one cell while multicellular organisms (“multi” means many) are organisms that consist of more than one cell. Even though unicellular organisms consist of only one cell, the organisms can carry out all the processes of life such as growth and reproduction. Unicellular organisms
Euglena has the characteristics of both plants and animals. Euglena can make its own food using sunlight like plants and move like animals. Euglena
Amoeba
Paramecium
Unicellular organisms in the animal kingdom are Amoeba and Paramecium that live in watery areas.
A unicellular organism in the plant kingdom is Chlamydomonas. Chlamydomonas
Figure 2.9 Examples of unicellular organisms
Multicellular organisms
Spirogyra
Hydra
Mucor
My body consists of many cells.
I am a multicellular organism.
I am also a multicellular organism. Figure 2.10 Examples of multicellular organisms Chapter Bab 2
53
2.3
21
CPS
Aim: To identify the characteristics of unicellular organisms and multicellular organisms Instruction 1. Work in groups. 2. Each group has to present the characteristics of unicellular organisms and multicellular organisms in class using a mind map.
The Types and Functions of Animal Cells and Plant Cells Animal Cells Nerve cells Contain long fibres that function to carry information in the form of impulse to all parts of the body. Epithelium cells Form a layer that protects organs in the body. These cells also secrete mucus.
Muscle cells Contract and relax muscles to enable movement.
Video on Cell Structure and Function
Ovum
Red blood cells • Have no nucleus. • Biconcave disc shaped to increase surface area • Contain haemoglobin that functions to transport oxygen to all parts of the body. • Transport carbon dioxide from cells in all parts of the body to the lungs.
Sperm
Reproductive cells Sperms carry male genetic materials and an ovum carries female genetic materials.
White blood cells Change their form to surround foreign particles and destroy them.
Figure 2.11 The types of cells in our bodies 54
Bab 2 2 Chapter
Sel Sebagai Chapter 2: Cell Unit asAsas the Basic Hidupan Unit Saintifik of Life Pengenalan kepada Penyiasatan
Plant Cells Cuticle Upper epidermis
Xylem
Epidermal cells Function to reduce water loss, allow gaseous exchange and absorption of water and nutrient.
Phloem O2
Air space between cells CO2
Guard cell
Lower epidermis
Cross section of a leaf
Palisade cells Contain chlorophyll to absorb sunlight to carry out photosynthesis.
Stoma
Guard cell Epidermal cell
Guard cells Guard cells control the opening and closing of stoma. A stoma is a small pore between the guard cells. The stoma is usually open during the day to carry out photosynthesis. The stoma is closed at night or when the plant loses a lot of water on a hot day.
Epidermis tissue Root hair
Root hair cells Root hair cells increase the surface area to absorb more water and nutrient from the soil.
Figure 2.12 The types of cells in plants
The Formation of an Organism A group of cells with specific functions combine to form a tissue. A group of tissues combine to form an organ. A group of organs combine to form a system. Various systems combine to form an organism. The cell organisation of forming multicellular organisms is shown in Figure 2.13.
Science Exploration Skin is the largest organ in the human body.
Chapter Bab 2
55
The order of cell organisation Cell
Organ
Tissue
System
Cell Most cells inside an organism have specific functions.
In animals
Epithelium cell
Organism In plants
Epidermal cell
Tissue Cells with the same function combine to form a tissue.
Epithelium tissue
Organ Different tissues that work together to perform a specific function forms an organ.
Muscle Epithelium tissue Stomach
Nerve tissue
Mouth Oesophagus Stomach
Large intesine
Small intestine
Epidermal tissue
Leaf
System A few organs with related functions that work together for a specific function forms a system.
Leaf Stem
Root Water
Digestive system
Transportation system
Organism All the systems work together to support an organism.
Organism
56
Bab 2 2 Chapter
Organism
Figure 2.13 Cell organisation in organisms
Sel Sebagai Chapter 2: Cell Unit asAsas the Basic Hidupan Unit Saintifik of Life Pengenalan kepada Penyiasatan
2.4
21
ICS
Aim: To study the way organisms are formed from basic unit of cells Instruction 1. Work in groups. 2. Each group has to present how cells form an organism using multimedia presentation in class.
Systems in the Human Body There are various systems that carry out important functions inside the human body. Each system consists of a few organs that work together to carry out a specific function. The various functions of all systems must be coordinated so that the human body can carry out all life processes or activities effectively. Systems in the human body https://en.wikipedia.org/wiki/Human_body
Excretory system
Skeletal system Skull
Skin
Lung Kidney Bone
Removes excretory waste from the body. Lymphatic system
Supports the body and protects the inner organs such as the lung and heart. Digestive system
Mouth Lymph
Oesophagus Large intestine
Drains lymphatic fluid into blood vessels to protect the body from infections of bacteria, virus and others.
Stomach Small intestine
Breaks down complex food into simpler form so that it is more easily absorbed by the body. Chapter Bab 2
57
Muscular system
Integumentary system
Nervous system Brain
Skin
Spinal cord
Muscle
Nerve
Helps in the movements of the body and inner organs.
Protects the body from dehydration and regulates Carries information from the brain to body temperature. the entire body in the form of impulse.
Blood circulatory system
Respiratory system Nose
Heart
Lung
Blood vessel
Carries oxygen, nutrients and hormones to all parts of the body.
Absorbs oxygen and releases carbon dioxide from the body.
Endocrine system
Reproductive system
Pituitary Thyroid
Ovary
Adrenal Pancreas
Ovary
Testis
Produces hormones required to coordinate reactions in the body.
Testis Penis
Produces sperms and ovum to produce offspring.
Figure 2.14 Examples of systems in the human body
Cell organisation form various organisms. We should be thankful to God for the existence of various organisms that are beneficial to us. 58
Bab 2 2 Chapter
Sel Sebagai Chapter 2: Cell Unit asAsas the Basic Hidupan Unit Saintifik of Life Pengenalan kepada Penyiasatan
2.1 1. Fill in the blanks with correct answers. (a) Blood plasma, red blood cells, white blood cells and in blood are the basis for the system. (b) , and play a role in the excretory system in humans.
2. Match each plant cell with its correct function. Palisade cell Absorbs sunlight for photosynthesis Epidermis cell Controls the opening and closing of stoma Root hair cell Reduces water loss Guard cell Absorbs water from soil 3. Name the structure in a plant cell which has the following function.
Protects and maintains cell shape =
Cell Respiration and Photosynthesis
2.2 Let’s learn • • • •
Communicate about the process of cell respiration. Communicate about the process of photosynthesis. Differentiate the process of cell respiration and photosynthesis. Explain how the process of cell respiration and photosynthesis complement each other.
What is Respiration?
Respiration can be divided into external respiration (breathing) and internal respiration (cell respiration). Breathing involves exchange of gases between the organism and environment whereas cell respiration is the oxidation process and break down of glucose that occur inside living cells to release energy.
Cell Respiration Cell respiration is the process of breaking down food to release energy. The energy released will be used for all life processes that occur inside the body. Cell respiration requires oxygen and glucose to produce energy, carbon dioxide and water. Glucose
+ Oxygen → Carbon dioxide
+ + Water Energy
Chapter Bab 2
59
Photosynthesis Plants make their own food through photosynthesis. Food made by plants is kept in the form of glucose known as starch. Therefore, the presence of starch in leaves shows the occurrence of photosynthesis. What are the requirements for photosynthesis? Light energy, carbon dioxide, water and chlorophyll are needed for photosynthesis. Before investigating the requirements for photosynthesis (Experiment 2.1 to 2.4), we need to know how to carry out a test to identify the presence of starch in a leaf first. Test for the presence of starch
Notes Ethanol
Boiling water
Ethanol removes chlorophyll in the leaf.
Hot water
Heat Plucked
Iodine solution White tile
Hot water
1. Make sure that ethanol is not exposed to heat sources such as flame from the Bunsen burner as ethanol is flammable. 2. Always be careful when handling iodine solution and hot water.
Figure 2.15 Steps to carry out the test for the presence of starch
Instruction: (a) (b) (c) (d)
Dip a leaf into boiling water to break the cell wall of the leaf to soften it. Half fill a boiling tube with ethanol and put the leaf into it. Place the boiling tube into a beaker containing hot water. After 5 minutes, take out the leaf from the boiling tube. Observe the colour changes on the leaf. (e) Dip the leaf into the hot water for a few seconds to soften the leaf. (f) Place the leaf on a white tile and put a few drops of iodine solution on it. Observation: The colour of iodine solution changes from brown to dark blue if starch is present.
60
Bab 2 2 Chapter
Sel Sebagai Chapter 2: Cell Unit asAsas the Basic Hidupan Unit Saintifik of Life Pengenalan kepada Penyiasatan
Experiment
2.1
Problem statement: Is light energy needed in photosynthesis? Hypothesis: Plants need light energy for photosynthesis. Aim: To investigate the need for light energy in photosynthesis. Variables Manipulated variable: The presence of sunlight Responding variable: The colour change of iodine solution Constant variable: Type of plants Materials and apparatus: Two similar plants in different pots, hot water, ethanol, iodine solution, boiling tube, white tile, dropper, forceps, beaker, Bunsen burner, tripod stand, wire gauze. Procedure 1. Keep two similar plants in a dark place for two days to remove starch. 2. After two days, place one of the plants under sunlight (Figure 2.16). 3. After a week, pluck a leaf from each plant. 4. Test for the presence of starch on both leaves and record the observations.
In the dark
Under sunlight
Figure 2.16
Conclusion: Is the hypothesis accepted or rejected? Give your reasons.
Experiment
2.2
Problem statement: Is chlorophyll needed in photosynthesis? Hypothesis: Plants need chlorophyll for photosynthesis. Aim: To investigate the need for chlorophyll in photosynthesis. Variables Manipulated variable: The presence of chlorophyll Responding variable: The colour change of iodine solution Constant variable: Type of plants
Notes A variegated leaf is a leaf which has a few colours. Some leaves are reddish and has little chlorophyll behind the red pigment.
Materials and apparatus: A variegated leaf, hot water, ethanol, iodine solution, boiling tube, white tile, dropper, forceps, beaker, Bunsen burner, tripod stand, wire gauze. Procedure 1. Pluck a variegated leaf which has been exposed to sunlight for a few hours (Figure 2.17). 2. Draw a diagram showing the green colour distribution of the leaf.
Non-green part of leaf Green part of leaf
Figure 2.17 A variegated leaf
Chapter Bab 2
61
3. Test for the presence of starch on the leaf. 4. Record your observations. Conclusion Is the hypothesis accepted or rejected? Give your reasons.
Experiment
2.3
Problem statement: Is carbon dioxide needed in photosynthesis? Hypothesis: Plants need carbon dioxide for photosynthesis. Aim: To investigate the need for carbon dioxide in photosynthesis. Variables Manipulated variable: The presence of carbon dioxide Responding variable: The colour change of iodine solution Constant variable: Type of plants
Video on photosynthesis
Materials and apparatus: Two similar plants in different pots, hot water, ethanol, iodine solution, potassium hydroxide solution, bell jar, boiling tube, white tile, dropper, forceps, beaker, Bunsen burner, tripod stand, wire gauze, glass plate with vaseline. Procedure 1. Place two similar plants in a dark place for two days to remove starch. 2. Place the two plants in two different bell jars and label A and B for each plant (Figure 2.18). 3. In bell jar A, put a beaker of potassium hydroxide solution. Potassium hydroxide solution is used to absorb carbon dioxide in the air. 4. Place both plants under sunlight for four days. Sunlight
Sunlight
Air without carbon dioxide
Bell jar
Green plant
Potassium hydroxide solution
A
62
Bab 2 2 Chapter
Glass plates with vaseline
Figure 2.18
B
Sel Sebagai Chapter 2: Cell Unit asAsas the Basic Hidupan Unit Saintifik of Life Pengenalan kepada Penyiasatan
5. Test for the presence of starch on the leaves. 6. Record your observations. Conclusion: Is the hypothesis accepted or rejected? Give your reasons.
Experiment
2.4
Problem statement: Is water needed for photosynthesis? Hypothesis: Plants need water for photosynthesis. Aim: To investigate the need for water in photosynthesis. Variables Manipulated variable: The presence of water Responding variable: Colour change of the iodine solution Constant variable: Type of plants Materials and apparatus: Two similar plants in different pots, water, hot water, ethanol, iodine solution, boiling tube, white tile, dropper, forceps, beaker, Bunsen burner, tripod stand, wire gauze. Procedure 1. Keep two similar plants in a dark place for two days to remove starch. 2. After two days, place the two plants under sunlight. Label the plants as A and B. 3. Water plant A everyday (Figure 2.19). 4. After a week, pluck a leaf from each plant.
A Pasu P
Figure 2.19
B Pasu Q
5. Test for the presence of starch on the leaves. 6. Record your observations. Conclusion Is the hypothesis accepted or rejected? Give your reasons. Chapter Bab 2
63
From the results of Experiment 2.1 to 2.4, it can be concluded that the process of photosynthesis requires light energy, chlorophyll, carbon dioxide and water to produce glucose and oxygen as shown in Figure 2.20. Carbon dioxide Sunlight
Oxygen Chlorophyll
Traps light energy
Glucose Light energy Carbon dioxide + Water Glucose + Oxygen Chlorophyll
The word equation for photosynthesis
Water
Figure 2.20 The process of photosynthesis
The Differences between Cell Respiration and Photosynthesis Table 2.1 shows the differences between cell respiration and photosynthesis. Table 2.1 The differences between cell respiration and photosynthesis
Cell Respiration Occurs in mitochondria Process to release energy Uses chemical energy in food Occurs in humans, animals, plants and microorganisms Breaks down glucose to produce energy Uses glucose and oxygen to produce carbon dioxide, water and energy Occurs at all times
64
Bab 2 2 Chapter
Photosynthesis Occurs in chloroplast Process to absorb energy Uses energy from light Occurs in plants and microorganisms Synthesises glucose Uses carbon dioxide and water to produce oxygen and glucose Occurs only in the presence of light
Sel Sebagai Chapter 2: Cell Unit asAsas the Basic Hidupan Unit Saintifik of Life Pengenalan kepada Penyiasatan
The processes of cell respiration and photosynthesis complement each other. During cell respiration, oxygen is absorbed and carbon dioxide is released. Released carbon dioxide will be used by plants to carry out photosynthesis. On the other hand, photosynthesis produces oxygen that is needed by all organisms for cell respiration. Sunlight
P
to ho
syn
thesis
All organisms use glucose and oxygen during cell respiration
Plants produce glucose and oxygen
Plants use carbon dioxide and water during photosynthesis
R
All organisms produce carbon dioxide and water es pi ra tio n
Figure 2.21 The processes of cell respiration and photosynthesis complement each other
2.2 1. Name the process that occurs in the diagram. What is the purpose of this process?
Oxygen Carbon dioxide
2. Fill in the blanks in the diagram shown below.
Green plants
produce
changes to
energy to maintain process of life and activity
during
Chapter Bab 2
65
66
Bab 2 2 Chapter
Compare and contrast animal cells with plant cells
Functions of structures in animal cells and plant cells
Examples: Amoeba Paramecium Euglena yeast
Organism that consists of only one cell
The preparation of slides of animal cells and plant cells
The structures in animal cells and plant cells
Unicellular organism
Living things are made up of cells
Examples: Human Mucor Hydra Cat Hibiscus
Organism that consists of more than one cell
Multicellular organism
Cell – Structure, function and organisation
Organism
System
Organ
Tissue
Cell
Cell Organisation
Cell as the Basic Unit of Life
Cell respiration
The process of cell respiration and photosynthesis complements each other
The difference between the process of cell respiration and photosynthesis
Photosynthesis
Cell respiration and photosynthesis
Sel Sebagai Chapter 2: Cell Unit asAsas the Basic Hidupan Unit Saintifik of Life Pengenalan kepada Penyiasatan
After learning this chapter, you are able to: 2.1 Cell – Structure, Function and Organisation Explain that living things are made up of cells that carry out life’s functions and undergo cell division. Demonstrate the preparation of slides of animal cells and plant cells using the correct procedures. Communicate about each structure in cells with their functions as well as compare and contrast animal cells with plant cells. Explain with examples the characteristics of unicellular and multicellular organisms for animal cells and plant cells.
Differentiate the types and functions of animal cells and plant cells. Conceptualise the formation of a plant and an animal with reference to the sequence of cell organisation: Cell → tissue → organ → system → organism Appreciate and be amazed by the existence of various organisms.
2.2 Cell Respiration and Photosynthesis Communicate about the process of cell respiration. Communicate about the process of photosynthesis. Differentiate the process of cell respiration and photosynthesis. Explain how the process of cell respiration and photosynthesis complement each other.
Summative Practice
2
1. Label structures P, Q and R in Figure 1. P:
Q:
R:
Figure 1
2. Mark (✓) in the boxes which represent organs.
Epithelium
Sperm
Kidney
Ovum
Lung
Chapter Bab 2
67
3. Name the cells below. (a)
(b)
(c)
Figure 2
4. If a plant cell and an animal cell are observed under a microscope, what are the characteristics of the cells that enable you to identify the cell as a plant cell? 5. Explain why the skin is an organ and not a tissue. 6. Give one example of an organ. Predict the condition of a human if he loses the organ. 7. Figure 3 shows the organisation of a system in a human.
White blood cells
Heart Red blood cells
Tissue
System
Figure 3
State the system and discuss its functions.
8. Herbivores such as the cow shown in Photograph 1 eat grass. Energy from the grass reaches the cow and returns to the grass. How do living things depend on each other in this case? Discuss.
Photograph 1 68
Bab 2 2 Chapter
Chapter Koordinasi Sel Chapter Sebagai 3:2:Coordination dan Cell Unit Gerak asAsas the Balas Basic Hidupan andUnit Response of Life Pengenalan Pengenalan kepada kepada Penyiasatan Penyiasatan Saintifik Saintifik
9. Amirah and Azma collected a water sample from a pond. They found an organism inside a drop of the water when it was observed using a microscope.
Flagellum
Chloroplast
Figure 4
Amirah thinks that the organism is a type of animal but Azma feels that the organism is a type of plant. In your opinion, which is the better statement regarding the organism above? Give a reason. 10. Zuliha carried out an investigation to study cells that formed the heart. In your opinion, which cell in Figure 5 assists in the contraction and relaxation of the heart muscles? Give your reasons.
P
Q
R
Figure 5
11. Three students are talking about cells. Their conversation is as below. Mei Foong: In my opinion, all organisms consist of one cell only. Keetha: My opinion is that some organisms consist of one cell while other organisms consist of many cells to carry out various functions.
Hidayah: I do not agree. All living things are complex and consist of many cells to carry out various functions.
In your opinion, which student’s statement is correct? Give reasons to support your choice.
Chapter Bab 2 3
69
Chapter
3
Coordination and Response
Humans and living things move all the time. How do humans and living things regulate the internal environment inside the body?
Let’s study: Homeostasis in Living Things 70
Bab 3 3 Chapter
Koordinasi Chapter 3: Coordination dan Gerak Balas and Response Pengenalan kepada Penyiasatan Saintifik
ETIN SCIENCE BPEURALTULRE REGULATOR ST TEM
OUR BODY IS THE BE
cal reactions in the body ys at 37°C so that chemi sta lly know era gen re atu per dy temperature. Do you ur body tem e, 37°C is the normal bo for ere re Th atu ly. ent per ici tem eff dy on bo Normal can functi normal body temperature? a e hav a o als for ds re bir atu per and that mammals le, normal body tem es of animals. For examp rcupine is around 31°C. differs according to the typ body temperature for a po al rm re. no ile wh °C 39 ut rease the body temperatu magpie is abo produces heat that will inc dy bo r re. ou g, atu nin per run tem are dy When we eat to reduce the bo on our body will produce sw r body cells cannot functi Thus, the sweat glands in p to its normal range, ou dro t no al es rm do no re the atu m per If the body tem re exceeding 6°C fro se death. Body temperatu efficiently and it might cau fever should be th th. Therefore, patients wi too high. temperature will cause dea fro dy temperature m rising bo ir the t ven pre to y sel monitored clo
O
Homeostasis Transpiration Pulse count
Regulation Response Biological action
Chapter Bab 3
71
3.1
Homeostasis in Living Things
Let’s learn • • • •
Communicate about meaning of homeostasis. Explain with examples the systems involved with homeostasis in humans and animals. Explain with examples the systems involved in plant homeostasis. Appreciate the importance of homeostasis in humans and living things.
W
hat is meant by homeostasis? Homeostasis refers to the maintenance of the internal environment in the body of an organism, such as temperature, water, pH and blood pressure to be in a balanced and stable condition. The maintenance of the internal environment in the body of an organism in a balanced and stable condition, allows all living processes in the body of the organism to work well. If the internal conditions are not balanced, for example the temperature is too high, the cells of the organism may die.
Homeostasis comes from two Greek words, ‘homeo’ meaning ‘similar’ and ‘stasis’ meaning ‘stable’.
Homeostasis in Humans Have you ever used an oven? Do you know that a thermostat is used to control the temperature of an oven? If the thermostat detects the temperature of the oven is too high, the heating function in the oven will switch off and the temperature will decrease. If the thermostat detects the temperature of the oven is too low, the heating function in the oven will switch on to increase the temperature.
Photograph 3.1 Thermostat of an oven
The same goes to our body which has a mechanism that can regulate body temperature, water content and others to be in a balanced and stable condition.
Photograph 3.2 Homeostasis in our body allows processes in the body to function efficiently 72
Bab 3 3 Chapter
Koordinasi Chapter 3: Coordination dan Gerak Balas and Response Pengenalan kepada Penyiasatan Saintifik
Homeostatic Control Process When the internal environment in our body such as the body temperature increases, the control centre at the brain will detect the changes. A corrective mechanism will then take place and the temperature will reduce to its normal range. When the body temperature decreases, a corrective mechanism will take place and the temperature will rise to its normal range (Figure 3.1). Control centre
Corrective mechanism Decreases
Increases Normal Temperature Range
Normal Temperature Range Increases
Decreases Control centre
Corrective mechanism Figure 3.1 Homeostatic control process
Homeostasis is important to humans. Among the most important homeostasis in the human body are the regulation of water and body temperature.
How does my body regulate water content?
3.1
How does my body regulate body temperature?
21
ICS
Aim: To gather information about homeostasis in our body Instruction 1. Work in groups. 2. Each group has to collect information on homeostasis such as regulation of water content and body temperature. Information can be obtained from the Internet, magazines and other sources. 3. Discuss the information that you have collected in your group. 4. After that, each group has to present their discussion in class using multimedia presentation. Chapter 3
73
Regulation of Water Content Systems that are involved in water regulation are the excretory system and endocrine system. Examples of organs involved are kidneys and brain. Brain
Corrective mechanism • The brain will stimulate the secretion of a hormone so that the kidneys increase the production of urine. • More urine is produced. Detected by the brain Water content in the body increases when we drink water.
Water content in the body decreases.
Increases Normal water level Decreases Water content in the body increases.
Corrective mechanism Water content in the body decreases when we sweat.
Brain
• The brain will stimulate the secretion of a hormone so that the kidneys will decrease the production of urine. • Feel thirsty.
Detected by the brain Figure 3.2 The regulation of water content 74
Bab 3 3 Chapter
Koordinasi Chapter 3: Coordination dan Gerak Balas and Response Pengenalan kepada Penyiasatan Saintifik
Regulation of Body Temperature Systems that are involved in regulation of body temperature are the excretory system and endocrine system. Examples of organs involved are skin, brain and skeletal muscles. Corrective mechanism
Brain
Blood vessels dilate Hairs lie flat Increase sweating Activity of the skeletal muscles and certain hormone secretion will reduce and eventually, decrease the body temperature. • Less urine • • • •
Detected by the brain
During a hot day, our body temperature will increase. Body temperature decreases. Increases Normal temperature (37°C) Decreases Body temperature increases.
During a cold day, our body temperature will decrease.
Corrective mechanism • • • •
Detected by the brain Brain
Blood vessels constrict Hairs stand erect Decrease sweating Skeletal muscles will contract and relax actively and it will cause an individual to shiver to increase the body temperature. At the same time, certain hormones will be secreted to increase body metabolism.
Figure 3.3 The regulation of body temperature Chapter Bab 3
75
Higher surrounding temperature
Lower surrounding temperature
Sweat glands produce more sweat to cool the skin when sweat is evaporated.
Erect hairs trap a layer of air that acts as a heat insulator.
Hairs lie flat to reduce air trapped on the skin so that heat can be released easily.
Hairs stand erect
Hairs lie flat Blood vessels dilate
Blood vessels constrict
Sweat
Skin layer
Sweat glands
Blood vessels dilate to let more blood flow close to the skin to increase heat loss.
Blood vessels constrict to let more blood flow away from the skin to reduce heat loss.
Figure 3.4 The condition of skin layer during higher and lower surrounding temperature Video of the role of skin thermoregulation
Experiment
3.1
Problem statement: Do we sweat in a hot or cold condition? Hypothesis: We sweat in a hot condition. Aim: To study how the biological actions respond to changes in temperature. Variables Manipulated variable: The surrounding temperature Responding variable: Presence of sweat Fixed variable: Time taken Materials and Apparatus: Stopwatch 76
Bab 3 3 Chapter
Koordinasi Chapter 3: Coordination dan Gerak Balas and Response Pengenalan kepada Penyiasatan Saintifik
Procedure 1. Enter the laboratory without switching on the fans for 10 minutes. 2. Record whether or not you are sweating. 3. Then, switch on the fans for 10 minutes. 4. Record whether or not you are sweating. Results The surrounding temperature
Presence of sweat
Hot (Fan is switched off)
Cool (Fan is switched on)
Question 1. What will happen to the body when we are in a higher surrounding temperature? Conclusion: Is the hypothesis accepted? Give your reason.
Experiment
3.2
Problem statement: Does the pulse count increase when executing heavy tasks? Hypothesis: Pulse count will increase when executing heavy tasks. Aim: To study how biological actions respond to pulse count. Variables Manipulated variable: Types of activities Responding variable: Pulse count Fixed variable: Time taken Materials and apparatus: Stopwatch, a student from each group. Procedure 1. Choose one student from each group to carry out the activities planned which are at rest, walking and jogging for 5 minutes. 2. Then, count the pulse of each student for a minute by placing two fingers on their wrist and record the reading after each activity (Photograph 3.3).
Photograph 3.3 The way to count pulse
Chapter Bab 3
77
3. Record the results in the table as shown below. Results Group number
Student’s name
At rest
Pulse count Walking
Jogging
1 2 3 4
Questions 1. What is shown by the data collected? 2. What other observations can be seen on students after doing heavy tasks? 3. Why is sweat produced when doing heavy tasks? Conclusion: Is the hypothesis accepted or rejected? Give your reason.
Homeostasis in Animals Homeostasis also occurs in animals. Animals like cats and dogs do not have sweat glands except on their sole. How do they maintain homeostasis during changes in surrounding temperature? I lick my fur to reduce my body temperature.
I hang my tongue out so that the temperature decreases.
My fur stands erect when it is cold to trap heat.
Photograph 3.4 Responses of animals towards changes in surrounding temperature 78
Bab 3 3 Chapter
Koordinasi Chapter 3: Coordination dan Gerak Balas and Response Pengenalan kepada Penyiasatan Saintifik
How do reptiles such as lizards maintain homeostasis towards changes in surrounding temperature?
Cold Surrounding: • • • • •
Hot Surrounding: • The heart beats faster • Movements become faster • Metabolism rate increases • Body temperature increases
Body activities become slower Muscles function more slowly Movements become slower Metabolism rate decreases Body temperature decreases
Photograph 3.5 Lizards regulate body temperature when the surrounding temperature changes
How do snails and bees maintain homeostasis towards the increase in surrounding temperature?
Loses a lot of water through evaporation on skin surface. Produces fluid and looks for humid places to reduce water loss.
B
How does homeostasis occur in the body of snakes and polar bears? 21
CPS
Photograph 3.6 Snail
Has waxy skin layer and loss of water vapour occurs through its spiracles. Closes spiracles between two breathing movements to reduce water loss.
Photograph 3.7 Bee Chapter Bab 3
79
1 In the afternoon
Homeostasis in Plants Observe the plant condition during different times in a day. Plants need sufficient water to prevent them from withering and die. How do plants regulate water content during hot and cold days? Water from plants are lost through a process known as transpiration. During transpiration, plants lose water from leaves in the form of water vapour to the surrounding through the stoma. This involves the transport system in plants.
2 In the evening
Photograph 3.8 Banana tree leaves roll up in the afternoon to avoid excessive water loss
• Transpiration helps plants to absorb and carry water and minerals from the soil to all parts of the plant (Figure 3.5). • Evaporation of water from the leaves cools the plant during hot days.
Key:
Science Exploration
Flow of water
Water vapour Stoma Cross section of a leaf
Almost 90% of water absorbed by the roots of plants is lost through transpiration.
2 Transpiration on leaves produces force that draws water from the stems of plants.
1 Roots of plants Root hairs
absorb water and minerals from soil.
Water in soil
Figure 3.5 Transpiration helps in water transportation from roots to leaves 80
Bab 3 3 Chapter
Koordinasi Chapter 3: Coordination dan Gerak Balas and Response Pengenalan kepada Penyiasatan Saintifik
Stoma Guard cells control the opening and closing of stoma. During the day, stoma opens to enable exchange of gas. At the same time, water vapour will be lost from the leaves and this will increase the rate of water intake by the roots. During the day
Guard cell Opened stoma
During the day, stoma opens to enable more water to be evaporated from the leaves through transpiration.
When the temperature is too high
Guard cell Closed stoma
When the temperature is too high, stoma closes to reduce water evaporated from the leaves through transpiration. Figure 3.6 The opening and closing of stoma Chapter Bab 3
81
3.2 Aim: To gather information on transpiration Instruction 1. Work in groups. 2. Each group has to collect information on transpiration such as its function in the regulation of water content in plants. Information can be obtained from the Internet, magazines and other sources. 3. Discuss the information that you have collected. 4. After that, each group has to present their discussion in class using multimedia presentation.
82
Bab 3 3 Chapter
Koordinasi Chapter 3: Coordination dan Gerak Balas and Response Pengenalan kepada Penyiasatan Saintifik
Importance of Homeostasis to Humans and Living Things Homeostasis in human body and living things is to provide the optimum conditions in the body so that cells can carry out metabolism activities efficiently. All chemical reactions in living cells are controlled by enzymes that are sensitive to surrounding changes. Changes in temperature will influence the enzyme activities. We should be grateful that homeostasis enables the internal environment of our body to be regulated and maintained in a balanced and stable condition. Imagine our life without homeostasis. What would happen if the temperature in our body or other living things continue to increase or decrease? What would happen if the water content in our body or other living things is lost without control?
Ouch, my body is getting warmer!
Ouch, my body temperature has not gone down yet!
Figure 3.7 Condition of humans and plants without homeostasis
3.3
21
ICS
Aim: To discuss the importance of homeostasis. Instruction 1. Work in groups. 2. Discuss the importance of homeostasis. Each student must give at least one idea. 3. Present the group discussion in the form of multimedia presentation such as PowerPoint in class.
3.1 1. What is homeostasis? 2. Give two examples of important regulation in the human body.
Chapter Bab 3
83
84
Bab 3 3 Chapter
Blood pressure
Water
Temperature
Example
Maintenance of internal environment in the body of an organism
Definition of Homeostasis
Regulation of body temperature
Pulse count increases when executing heavy tasks
Regulation of water
Homeostasis in Humans
Coordination and Response
Role of transpiration in water regulation
Homeostasis in Plants
Importance of homeostasis in humans, animals and plants
Ways of regulating body temperature
Homeostasis in Animals
Koordinasi Chapter 3: Coordination dan Gerak Balas and Response Pengenalan kepada Penyiasatan Saintifik
After learning this chapter, you are able to: 3.1 Homeostasis in Living Things Communicate about meaning of homeostasis. Explain with examples the systems involved with homeostasis in humans and animals. Explain with examples the systems involved in plant homeostasis. Appreciate the importance of homeostasis in humans and living things.
Summative Practice
3
1. How do plants control homeostasis? 2. How do our bodies respond to changes in temperature when we enter a very cold room? 3. What is the role of blood vessels in increasing heat loss? 4. What is the advantage of having a constant body temperature? 5. During exercise, our body loses a lot of water. Why do people who exercise need to drink water before feeling thirsty? 6. Why does our face look red after doing an active exercise but pale when feeling cold?
Quantity (ml)
7. The graph in Figure 1 shows that the quantity of sweat and urine changes with temperature. 200 180 160 140 120 100 80 60 40 20 0
Sweat
Urine
0
5 10 15 20 25 30 External body temperature (°C)
35
Figure 1
Chapter Bab 3
85
(a) (b) (c)
What would happen to the quantity of sweat when temperature increases? Explain why it happens. What would happen to the quantity of urine when temperature increases? Explain why it happens. Relate the relationship between both reasons in answers (a) and (b).
8. Khairul stayed in a house and was given the same quantity of food and drinks for three days. The quantity of urine produced was collected and measured. Table 1
Day Day one Day two Day three
Quantity of urine (ml) 1900 500 850
(a) Why must we ensure that the quantity of food and drinks for all three days is the same? (b) On which day did Khairul do the most vigorous activity? Give your reason(s). (Answer guide: relate it with the quantity of urine produced) 9. Why is wearing a few layers of thin clothing better than wearing a layer of thick clothing to maintain body temperature? 10. The statement below shows a hypothesis.
Plants regulate water content through the stoma.
Design an experiment to prove the hypothesis above.
86
The report must include: • Problem statement • Hypothesis • Aim • Variables • Apparatus and materials • Procedure • Data tabulation
Bab 3 3 Chapter
Koordinasi Chapter 3: Coordination dan Gerak Balas and Response Pengenalan kepada Penyiasatan Saintifik
11. The statement below shows the functions of skin. Skin is an excretory organ, protective organ of other organs and the organ that regulates body temperature. In your opinion, is the statement true? Give your reason. 12. The statement below shows a hypothesis. More urine is produced when we drink a lot of water compared to when we drink less water. Design an experiment to prove the hypothesis above.
The report must include: • Problem statement • Hypothesis • Aim • Variables • Apparatus and materials • Procedure • Data tabulation
Chapter Bab 3
87
Chapter
4
Reproduction
The average of live births occuring daily in Malaysia is 1,400 births. (Department of Statistics Malaysia, 2014). What is the importance of birth?
Let’s Study: Sexual and Asexual Reproduction Human Reproductive System Menstrual Cycle Fertilisation and Pregnancy 88
Bab 3 4 Chapter 3
Factors Affecting the Development of a Foetus and Baby Infertility and Contraception Plant Reproduction
Pembiakan Chapter 4: Reproduction Pengenalan kepada Penyiasatan Saintifik
SCIENCE BULLETIN UREATE
ROBERT EDWARDS, NOBEL LA
icine. He had awarded the 2010 Nobel Prize for Med British scientist, Robert Edwards, was of fertilisation lisation (IVF) technology, a method successfully invented the in vitro ferti t tube). which takes place in a glass dish (tes egg cell that IVF procedure involves fertilising an How is the IVF procedure done? The the father in a from a glass dish with sperm cells obtained has been removed from the mother in e of embryo. stag y earl left to grow until it develops into an laboratory. The fertilised egg cell is born as is it l unti us. The embryo grows in the uterus Then, the embryo is placed in the uter a baby. time on 0s. His research succeeded for the first Edwards’s research began in the 195 named test tube baby was born. The baby was 25th July 1978 when the world’s first Louise Brown. to ried couples with fertility problems His achievement has helped many mar ies bab tube since brought millions of test have children. The IVF technology has
A
into the world.
Sexual reproduction Asexual reproduction Fertilisation Vegetative reproduction Puberty
Menstruation Ovulation Implantation Placenta Pollination
Chapter 4
89
4.1
Sexual and Asexual Reproduction
Let’s learn • Compare and contrast sexual and asexual reproduction in animals and plants. • Reason the importance of reproduction. • Be grateful for the ability to reproduce and the continuation of life as a gift from God.
D
o you know what reproduction is? Reproduction is the process of producing new individuals from living organisms. Reproduction is the basic characteristic of each living organism. Photograph 4.1 indicates how humans and animals reproduce.
Science Career Doctors who specialise in this field are known as obstetricians and gynaecologists.
Humans reproduce by giving birth.
Chickens reproduce by laying eggs.
Whales reproduce by giving birth.
Photograph 4.1 Ways of reproduction for humans and animals
Reproduction can be divided into, sexual reproduction and asexual reproduction. The classification of reproduction can be seen in the following thinking map.
90
Chapter 4
Pembiakan Chapter 4: Reproduction Pengenalan kepada Penyiasatan Saintifik
Reproduction Sexual
Asexual
Involves reproductive cells
Does not involve reproductive cells Occurs in: • plants (onion, ginger, potato) • simple organisms (Amoeba, Hydra, Paramecium)
Occurs in: • humans • higher animals (mammal, bird, fish, reptile and amphibian) • flowering plants
Photograph 4.2 Humans reproduce sexually
Fish Bird Potato
Reptile
Onion Flowering plant Ginger Amoeba
Mammal Amphibian
Photograph 4.3 A few examples of living organisms that reproduce sexually
Paramecium
Hydra
Photograph 4.4 A few examples of living organisms that reproduce asexually Chapter 4
91
Sexual Reproduction Sexual reproduction is the main type of reproduction that is carried out by human, higher animals and plants. Human reproduction is not only to produce offsprings, but it also involves family bonding and love.
Antonie van Leeuwenhoek was the first scientist who studied sperm cell using a microscope in 1677.
Sexual reproduction involves two parents, which are • male parent that carries male reproductive cell • female parent that carries female reproductive cell
Male
has
produces
Testis Male gamete (sperm)
Female
has
produces Ovary Female gamete (ovum)
Figure 4.1 Process of gamete production
Sexual reproduction produces a new generation that is different from its parents and shows genetic variation. Do you know how a new generation is formed? What causes the formation of babies in the body of pregnant mothers? The first process involved is known as fertilisation. 92
Chapter 4
Pembiakan Chapter 4: Reproduction Pengenalan kepada Penyiasatan Saintifik
There are two types of sexual fertilisation which are internal fertilisation and external fertilisation. The differences between internal and external fertilisation are summarised in Table 4.1. Table 4.1 Differences between internal and external fertilisation
Internal fertilisation
Characteristics
External fertilisation
Nucleus of the male gamete fuses with the nucleus of the female gamete inside the body of the female parent.
Happens when
Nucleus of the male gamete fuses with the nucleus of the female gamete outside the body of the female parent.
The male parent releases sperm into the body of the female parent.
Place of fusion
The male parent releases sperm and the female parent releases ovum. This fertilisation occurs in the water.
The male gamete from the male reproductive organ will be released into the female reproductive organ which has the female gamete and fuses to form a zygote.
Process
The male gamete usually swims towards the ovum and fuses with it.
Sperm Ovum
Figure 4.2 Internal fertilisation of dragonflies
Figure 4.3 External fertilisation of fish
B
Why do fish ova have a layer of gel coating?
Chapter 4
93
Asexual Reproduction
Science Exploration Tissue culture is an example of biotechnology that produces new individuals. This technique produces new plants in a short time.
Asexual reproduction is a process of producing new individuals without involving reproductive cells.
Asexual reproduction occurs in simple organisms like Amoeba, Paramecium and Hydra. Plants like onion, ginger and potato also reproduce asexually. For asexual reproduction, only one parent is involved. Fertilisation does not occur in asexual reproduction. The new individuals produced are genetically identical to their parents. Variations do not occur among the new individuals. Various types of asexual reproduction is explained in Figure 4.5.
Figure 4.4 Tissue culture
Tissue culture www.isaaa.org
4.1 Aim: To gather and interpret information about sexual and asexual reproductions Instruction 1. Work in groups. 2. Discuss the differences and similarities between internal and external fertilisation. 3. Record your discussion in a table as below. Internal fertilisation
Characteristics
External fertilisation
4. Collect information from the Internet on the following types of asexual reproductions: (a) binary fission (b) budding (c) spore formation (d) vegetative reproduction (e) regeneration
94
Chapter 4
Binary fission of Amoeba
Two daughter cells
Cytoplasm divides
Nucleus divides Budding of Hydra
Bud
Two new individuals
Chapter 4
Figure 4.5 Asexual reproduction
Regeneration of Planaria
Cut
Examples: Flatworm, starfish and Planaria
Examples: Hydra and yeast
Parent cell of Amoeba
Examples: Amoeba, Paramecium and bacteria
• Regeneration occurs from the ability of the fragments of some organisms to grow and develop into completely new individuals.
• Budding is the process of forming a bud on the organism’s body. • A bud starts off as a swelling. Then, it develops and breaks off as a new young.
• Binary fission is the division of a single parent cell into two daughter cells.
Regeneration
Budding
Binary fission
Asexual Reproduction
Yeast
Bacteria
Sporangium Spore formation of ferns
Spore
Root
Scaly leaf Bud Vegetative reproduction of ginger
New plant
Examples: Carrot, strawberry, ginger, yam and potatoes
• Vegetative reproduction is a method of producing new plants from a vegetative part of a plant except the flower. • Example of vegetative parts are the roots, underground stems, runners, bulbs and leaves.
• Spore formation is the process of producing spores in the sporangium. • After the sporangium breaks, the tiny and light spores get scattered by the wind. • When they land on a moist place, they grow into new plants. Examples: Algae, fungus, fern and bacteria
Vegetative reproduction
Carrot
Spore formation
Fern
Pembiakan Chapter 4: Reproduction Pengenalan kepada Penyiasatan Saintifik
95
Vegetative Reproduction Vegetative part
Example of plant
Root Roots of parent plant will grow into new plants.
New plant
Root Carrot
Stem Stems of parent plant will grow into new plants.
Sweet potato
(a) Underground stem
Runner Node
New potato Old potato
(c) Bulb
(b) Runner
Grass
Adventitious root
Potato
Stem Onion
Leaf Leaves of parent plant will grow into new plants.
Adventitious root
Bud
New plant Begonia
Bryophyllum
The Importance of Reproduction
I incubate my eggs and take care of my offsprings to ensure my species keep on living.
All living organisms reproduce to produce new individuals. What would happen if a living organism does not reproduce? Reproduction is very important to increase the number of organisms of the species. The failure of an organism to reproduce can cause extinction. What are the other importance of reproduction?
B Reproduction increases the number of individuals of the same species
Reproduction transfers the genetic information to the new generation
Photograph 4.5 Importance of reproduction 96
Chapter 4
Predict what would happen to humans if the extinction of animal and plant species increases?
Pembiakan Chapter 4: Reproduction Pengenalan kepada Penyiasatan Saintifik
Be Grateful for the Ability to Reproduce and the Continuation of Life as a Gift from God Baby dumping cases have been increasing tremendously day by day. Do you know that the ability to reproduce is a gift from God which has to be appreciated? Baby dumping is a barbaric act and should not happen. The babies born are the descendants of the human species.
4.2
21
ICS
Aim: To discuss the importance of reproduction and the problems that will arise if reproduction decreases for all living things. Instruction 1. Work in groups. 2. Each group has to collect information on the importance of reproduction and the problems that will arise if an organism does not reproduce. 3. Present your discussion using a multimedia presentation.
4.1 1. What are the differences between sexual and asexual reproduction? 2. State the parts of the following plants that reproduce vegetatively. (a) Onion (c) Ginger (e) Potato (b) Yam (d) Lallang (f) Bryophyllum 3. What is the importance of reproduction to living things?
4.2
Human Reproductive System
Let’s learn • Identify the structures and function of the male and female reproductive systems. • Communicate about the physical changes that occur during puberty. • Compare and contrast the male gamete with the female gamete in the reproductive system.
H
umans reproduce sexually. The human reproductive system consists of the male and female reproductive system. What are the organs involved in both systems?
Both the male and female reproductive systems are very important. Married couples cannot produce offsprings if any of their reproductive system malfunctions. Let us study the structure of the male and female reproductive systems. Chapter 4
97
Male Reproductive System Urinary bladder Seminal vesicle Prostate gland Sperm duct Urethra Scrotum Testis Penis
Figure 4.6 The front view of male reproductive system
Figure 4.7 The side view of male reproductive system
Table 4.2 Parts and functions of the male reproductive system
Part
98
Chapter 4
Function
Seminal vesicle
Secretes nutritional fluid for the sperms
Urethra
A channel to discharge sperms and urine from the body
Sperm duct
Transports sperms from the testis to the urethra inside the body
Penis
Transfers sperms into the vagina of the female during copulation
Scrotum
Holds and protects the testes
Testis
Produces male gametes (sperms) and male sex hormones
Prostate glands
Secrete fluid which contains nutrients and protects sperm cell.
Pembiakan Chapter 4: Reproduction Pengenalan kepada Penyiasatan Saintifik
Female Reproductive System
Fallopian tube
Ovary Uterus Cervix Vagina
Figure 4.8 The front view of female reproductive system
Figure 4.9 The side view of female reproductive system
Table 4.3 Parts and functions of the female reproductive system
Part
Function
Fallopian tube
Place where fertilisation between sperm and ovum occurs
Ovary
Produces female gamete (ovum) and female sex hormones
Uterus (womb)
Place where the embryo develops and grows
Cervix
Produces mucus to enable sperms to swim into the uterus
Vagina
Receives sperms and as a channel through which a baby is born
Chapter 4
99
4.3 Aim: To observe the structures and function of the reproductive system. Instruction 1. Work in groups. 2. Observe the structures of the male and female reproductive systems from the Internet. 3. Draw and label the male and female reproductive organs on a manila card. 4. Present your drawing in class. 5. Display your work at the science corner of your class or in the laboratory.
Physical Changes that Occur During Puberty Puberty is the early stage of the maturity of the reproductive system. Adolescents who have reached puberty will experience growth and change emotionally, physically and physiologically.
Science in Life
Look at these photos! You’ve changed so much! I wonder how I will look when I grow up.
We will see when you reach puberty. You’ll look different too. You will be experiencing changes in your body during puberty.
Figure 4.10 Puberty causes changes in individuals 100
Chapter 4
Pembiakan Chapter 4: Reproduction Pengenalan kepada Penyiasatan Saintifik
Boys reach puberty at approximately 14-17 years old. Meanwhile, girls reach puberty earlier than boys, which is 10-12 years old. What are the changes that occur to boys and girls when they reach puberty?
Male
Female
Voice • Vocal cord (larynx) enlarges • Voice becomes deeper
Body • Breasts grow • Hips become firm and broader • Hair grows on the armpits
Body • Moustache and beard begin to grow • Hair grows on the face, armpits and chest
Reproductive organs • Testes produce sperms and sex hormones • Hair grows at pubic region • Penis and scrotum enlarge
Reproductive organs • Ovaries produce ova and sex hormones • Hair grows at pubic region • Menstrual cycle begins Figure 4.11 Changes that occur during puberty
Chapter 4
101
4.4 Aim: To discuss the changes that occur during puberty. Instruction 1. List the physical changes that occur during puberty. 2. Is it normal if an 18-year-old girl still has not had her menstruation yet? Explain your answer. 3. Suppose that you work as a magazine editor for an advice column. A teenager wants your advice on a serious acne problem. What advice will you give to him/her?
Comparison between the Male and Female Gametes You have learned from the previous subtopic that sperm is a male gamete or male reproductive cell, while ovum is the female gamete or female reproductive cell. Sperm is the smallest cell in the male’s body and its shape is like a tadpole. Ovum is the largest cell in the female’s body. Figure 4.12 shows the structures of sperm and ovum.
Nucleus
Head
Gel layer Nucleus Cytoplasm Cell membrane
Middle piece
Tail
Sperm
Ovum
Figure 4.12 The structures of a sperm and an ovum 102
Chapter 4
Pembiakan Chapter 4: Reproduction Pengenalan kepada Penyiasatan Saintifik
The head of a sperm contains nucleus that carries genetic and hereditary information to be transferred to the offspring. The tail enables the sperm to move or swim in the semen inside the vagina, uterus and Fallopian tube of the female reproductive system. The normal number of sperms released is 60 million per cubic centimetre. Ovum is spherical in shape with a diameter of about 0.1 mm. The nucleus contains genetic and hereditary information to be transferred to the offspring. The ovum is not able to move by itself. A normal woman usually produces one ovum per month. Figure 4.13 shows the comparison between sperm and ovum.
Not able to move
Able to move Carries genetic information
Produced by testis
Sperm
Produced by ovary
Ovum Female gamete
Male gamete
Smallest cell in the male’s body
Sexual reproductive cell
Largest cell in the female’s body
Figure 4.13 Comparison between sperm and ovum Science Exploration Ovum can live up to two days after being released from the ovary while sperms can live up to three or four days.
B
If a woman releases her ovum every 28 days for 35 years, how many ova has she released? Show your calculation.
Chapter 4
103
4.2 1. What is the importance of the reproductive system to males and females? 2. State the functions of the urethra, penis and scrotum in the male reproductive system. 3. State the functions of the Fallopian tube, vagina and uterus in the female reproductive system. 4. What is meant by puberty? 5. During puberty, teenagers will encounter body odour problem. Explain how this problem occurs. 6. If a woman’s ovaries are damaged, can she still get pregnant? Explain your answer.
4.3
The Menstrual Cycle
Let’s learn • Communicate about the menstrual cycle and the sequence of changes in the uterus lining during menstruation. • Relate the fertile phase of the menstrual cycle to the process of fertilisation. • Justify the importance of personal hygiene during menstruation.
W
omen will undergo menstruation when they reach puberty. Menstruation marks the beginning of the menstrual cycle for each woman. Menstruation is the breakdown of the lining of the uterine wall and discharge of blood through the vagina. Menstrual cycle refers to a series of changes that occurs in the uterine wall and the ovaries. Menstrual cycle also involves the formation and release of mature ovum. 28
1
Men stru ati on 2 ph 3 4
5
Premens trua lp ha 22 1 2 se 23 24 25
26
27
The menstruation of a female will stop when she reaches menopause which is around 48 – 55 years old.
e as 6
7
19
12
13
14
15
16
17
18
Chapter 4
F e r til e p h a s e
e
104
11
Figure 4.14 The menstrual cycle
Ovulation
ha s
9
20
8 10
Menstruation www.ubykotex.com/ en-us/periods
R e pa i r p
Menstrual cycle is controlled by the brain and endocrine system which secretes hormone. Normally, a menstrual cycle lasts for 28 days and it differs for each individual. There are various factors that affect the menstrual cycle such as nutrient intake, abrupt change in body weight, emotional changes and mental pressure. Figure 4.14 shows the phases in the menstrual cycle.
Science Exploration
Pembiakan Chapter 4: Reproduction Pengenalan kepada Penyiasatan Saintifik
Day 1 – 5
Day 6 – 11
Menstruation phase The uterine lining breaks down as menstruation begins and is discharged together with blood, unfertilised ovum and mucus.
Repair phase Uterine lining starts to rebuild and thicken. Blood vessels in uterine lining are formed and ready to receive the implantation of fertilised ovum.
Uterine lining breaking down and flowing out
Uterine lining thickening
Day 12 – 17
Day 18 – 28
Fertile phase An ovum is released from the ovary on the 14th day of the menstrual cycle (ovulation). The uterine lining continues to thicken. Fertilisation is likely to occur if sperms are present.
Premenstrual phase The uterine lining continues to thicken and becomes richly supplied with blood vessels. Implantation of an embryo is ready if fertilisation occurs. The menstrual cycle will repeat if fertilisation does not occur.
Ovum
Uterine lining continues to thicken
Figure 4.15 The phases in the menstrual cycle Chapter 4
105
Importance of Personal Hygiene During Menstruation Urinary Tract Infection (UTI) http://www.dettol. com.my/my/ illnesses/urinarytract-infections/
Personal hygiene during menstruation is very important to ensure the reproductive system is not infected with microorganisms like bacteria, virus and fungi. How do you manage your personal hygiene during menstruation? Figure 4.16 shows the ways of practising good personal hygiene during menstruation and their importance.
1
During menstruation, a woman must change her sanitary pad 3-4 times a day to prevent the infection of bacteria and virus that might cause urinary tract infection (UTI).
Change sanitary pad 3-4 times a day
2
A menstruating woman is encouraged to bathe frequently to clean her body.
Clean your body
Figure 4.16 The importance of personal hygiene during menstruation
What would happen if a woman experiences irregular menstruation?
An irregular menstruation refers to a condition where a woman does not experience menstruation every month, has too long or too short menstrual cycles. Irregular menstruation might be caused by several factors such as an increase in body weight, hormonal imbalance, emotional disruption, excessive exercise and can also be caused by cervical tumour.
106
Chapter 4
B Why does the emotional state of a woman affect her menstrual cycle?
Pembiakan Chapter 4: Reproduction Pengenalan kepada Penyiasatan Saintifik
Irregular menstruation can cause negative effects to a woman’s health. Some of the negative effects of irregular menstruation to woman are: 1. Infertility – Irregular menstrual cycle is an early sign of having reproductive system problems. A late treatment can cause serious health problems such as ovarian cancer, cervical cancer and uterus cancer. 2. Having difficulties in family planning – Irregular menstrual cycle causes a woman to have difficulties in determining her fertile day. Hence, it is hard to plan a pregnancy. 3. Health problems such as anaemia – Irregular menstrual cycle can cause a long menstruation. This causes an excessive loss of blood. The body becomes weak and the woman faints easily.
4.3 1. Explain the phases of menstrual cycle. 2. At what age does a woman start to experience menstruation and how long does it last? 3. What is ovulation and where does ovulation normally occur? 4. Is it true that you cannot wash your hair, drink cold water, eat ice cream or play sport during menstruation? Explain your answer.
4.4
Fertilisation and Pregnancy
Let’s learn • Communicate about the process of fertilisation and the implantation of embryo. • Justify the importance and functions of placenta and umbilical cord. • Describe the development of a zygote into an embryo and subsequently into a foetus during pregnancy until birth.
ou have learned in subtopic 4.1, that fertilisation is a fusion between sperm and
Y
ovum. What happens after fertilisation? What happens after the fertilisation between sperm and ovum?
After the fertilisation, the woman will get pregnant, zygote will form and grow in the uterus until birth.
Chapter 4
107
2 If an ovum is present in the Fallopian
tube, fertilisation may occur. Sperm will fuse with ovum in the Fallopian tube and form a zygote.
Fallopian tube
Fertilisation
Ovary
3 After fertilisation, the zygote will divide
itself and become a ball of cells known as embryo. The embryo will be implanted on the uterine wall at the uterus.
Sperm
1 Sperms will swim
into the vagina during copulation.
Figure 4.17 The process of fertilisation and embryo implantation
The implanted embryo will grow and become a foetus that resembles a human (baby). This process is known as pregnancy. After approximately 38 weeks, the foetus will be born. Figure 4.18 shows the development of zygote to embryo until birth.
108
Chapter 4
Pembiakan Chapter 4: Reproduction Pengenalan kepada Penyiasatan Saintifik
Week 1 – 4 • Hands and feet will start to form. • The embryo has a tiny tail.
Week 7-9 • Nose, ears and fingers will be visible.
Week 10-19 • Embryo will look like a baby. • The embryo is now known as a foetus.
Video on Embryonic Development
Week 20-37 • Foetus will resemble a baby.
Week 38-40 • Foetus is formed completely. • The foetus turns until the head is engaged at the cervix. • The muscle of the uterine lining will contract strongly, the amnion will burst and amniotic fluid will be released. • Foetus is pushed out of the uterus through the vagina and then out of the body.
Figure 4.18 The growth of zygote to embryo and foetus until birth
Chapter 4
109
The Importance and Functions of the Placenta and the Umbilical Cord An embryo grows and develops into a foetus in a sac that is surrounded by a membrane known as amnion. Amnion contains fluid to protect the foetus. How does a foetus obtain nutrients and oxygen inside the uterus? How does a foetus remove its waste?
Placenta • Made up of tissue from both mother and the embryo • Place where exchange of oxygen and carbon dioxide, supply of nutrients and removal of waste materials through the mother’s blood and the foetus occur. Umbilical cord • Tube which connects the foetus to the placenta • There are blood vessels inside the tube to transport blood to and from the foetus Uterine wall • Consists of muscular wall • The place where the embryo is implanted and develops
Science Exploration Amniocentesis test is done to detect a few types of birth defect such as Down syndrome and muscle contraction. An amount of amniotic fluid is taken and tested.
Amnion • Membrane that forms a sac and contains fluid
Foetus • Embryo develops to form a foetus
Amniotic fluid • Acts as a cushion to absorb concussion and protects the foetus from injuries
Figure 4.19 Functions of placenta, umbilical cord, uterine wall, amniotic fluid and amnion
4.4 1. If embryo implantation occurs on the uterine lining, will menstruation occur? 2. Explain the development of zygote after fertilisation. 3. Complete the flow chart below on the development of zygote. Zygote 4. State the functions of amnion, placenta and umbilical cord.
110
Chapter 4
Pembiakan Chapter 4: Reproduction Pengenalan kepada Penyiasatan Saintifik
4.5
Factors Affecting the Development of a Foetus and Baby
Let’s learn • Relate the importance of taking nutritious food during pregnancy to the health of both mother and foetus. • Justify the importance of avoiding the intake of harmful substances to the foetus. • Justify the benefits of breastfeeding compared to formula milk on the infant’s development. • Realise that every living creature has a right to live even if it is in the womb.
W
hy is the nutritional requirement between a woman who is pregnant and one who is not pregnant different? You have learned foetus obtains nutrients and oxygen from the mother in subtopic 4.4. A pregnant woman must have a healthy and balanced diet and take good care of her health to deliver a healthy baby. The calorie requirement for a pregnant woman is higher. Figure 4.20 shows the daily calorie requirement of a pregnant woman.
Carbohydrate • Pregnant: 11 592 kJ • Not pregnant: 9 450 kJ
Vitamin A • Pregnant: 900 µg • Not pregnant: 750 µg
Protein • Pregnant: 85 g • Not pregnant: 39 g
Calcium • Pregnant: 1 000 – 1 500 mg • Not pregnant: 400 – 500 mg
Iron • Pregnant: 15 mg • Not pregnant: 10 mg
Vitamin C • Pregnant: 50 mg • Not pregnant: 30 mg
Figure 4.20 Daily calorie requirement of a pregnant woman Chapter 4
111
The intake of nutrients by a pregnant woman must be balanced and contain more carbohydrate, fat, protein, folic acid, vitamin C, calcium, phosphorus, iron and fibre. Each of the nutrients plays a vital role for the health of the mother and her baby. Figure 4.21 shows the nutrients which are needed by a pregnant woman.
Fibre • Examples: cereal, vegetables and fruits • Function: prevents constipation
Vitamin C • Examples: citrus fruits, guava and tomatoes • Functions: for skin health of foetus and mother and to prevent bleeding gums
Iron • Examples: liver, red meat and fish • Function: formation of haemoglobin to prevent anaemia
Protein • Examples: chicken, red Folic acid meat, fish, milk and • Examples: broccoli, spinach cheese and groundnuts • Function: important for • Function: important for the the growth of new cells nervous system development of the foetus of the foetus
Calcium and phosphorus • Examples: anchovies, cheese and milk • Functions: for a healthy formation of foetus bones and to protect the bones and teeth of the mother
What are the nutrients needed by a pregnant woman?
Figure 4.21 Nutrients needed by a pregnant woman 112
Chapter 4
Carbohydrate and fat • Examples: rice, bread, butter and cheese • Function: provide energy for daily activities
Pembiakan Chapter 4: Reproduction Pengenalan kepada Penyiasatan Saintifik
Pregnant women must not smoke and consume alcohol or drugs. The effects of smoking, alcoholic drinks and drugs on a pregnant woman are explained in Table 4.4. Table 4.4 The effects of smoking, intake of alcoholic drinks and drugs on a pregnant woman
Substance
Effects
Cigarette
• The baby may have low birth weight • The baby may have a higher mortality rate • The baby may become retarded and have physical disabilities • The baby may be born premature • Miscarriage of foetus may happen
Alcoholic drink
• The baby may be born with Foetal Alcohol Syndrome • Foetal development may be delayed • The brain, nervous system and the heart may be damaged
Drug
• Foetal defects may occur
Science Exploration Characteristics of a baby who suffers from Foetal Alcohol Syndrome: • born with a low birth weight • small head measurement • retarded • facial abnormalities
B Why is having frequent x-ray tests not good for a pregnant woman?
Importance of Breast Milk
ot eat A newborn baby does not have teeth and cann solid food. Babies depend solely on milk as their source them of nutrients. Breast milk is the best food for ula form to d because it is more nutritious compare milk. ients • Breast milk contains all the essential nutr for a baby. protect • Breast milk contains antibodies that can a baby from certain diseases. • Relationship between mother and baby will become closer and it is important for the emotional development of the baby. r • Baby who consumes breast milk has bette digestion compared to formula milk. Photograph 4.6 Breast milk is important for the development of a baby Chapter 4
113
Pregnant women must take good care of their health because every living thing has the right to live even though it is still in the womb. Therefore, a mother must ensure that her baby gets sufficient nutrients and avoid the intake of substances that might harm her own health and her baby.
Photograph 4.7 A healthy baby is born from a healthy family
4.5
21
ICS
Aim: To suggest ways to solve problem of abnormality in newborn babies due to the unhealthy lifestyle of pregnant mothers. Instruction Read the situation below carefully.
A pregnant woman practises an unhealthy lifestyle such as smoking, consumption of alcoholic drinks and drugs.
In groups, discuss (a) the risks towards the baby. (b) the healthy lifestyle that should be practised by the woman during pregnancy. (c) suggest ways to reduce the number of abnormal babies born due to the unhealthy lifestyle of mothers during pregnancy.
4.5 1. Why does a pregnant woman need more nutrients? 2. Why do the teeth and bones of a pregnant woman decay more easily? 3. Compare between breast milk and formulated milk.
114
Chapter 4
Pembiakan Chapter 4: Reproduction Pengenalan kepada Penyiasatan Saintifik
4.6
Infertility and Contraception
Let’s learn • Communicate the meaning of infertility and how to overcome them. • Differentiate methods of contraception. • Realise the importance of practising frequent health screening and to get immediate treatment for problems related to the reproductive system. • Criticise the abuse of knowledge on contraception methods and its effect to society.
Infertility
I
nfertility is the inability to produce offsprings. When a married couple is unable to bear children, the husband or wife or both may be sterile. Figure 4.22 shows the various factors of sterility in males and females.
Testes cannot produce sperms
Hormone imbalance
Ovaries cannot produce ovum Blockage in the Fallopian tubes
Low sperm count
Factors of sterility in males
Defective reproductive organs or organs infected with disease
Factors of sterility in females Abnormal uterus
Produces low quality sperms
Impotent
Health problems like diabetes
Tumour in the uterus
Figure 4.22 Factors of sterility in males and females
When the married couple has tried to conceive for more than a year, but they are still not successful, the couple is advised to seek medical consultation. Chapter 4
115
You may want to try hormone treatment, surgery or in vitro fertilisation. We’re still not blessed with a child. What can we do?
Figure 4.23 Scene of a couple consulting a doctor
Methods to Overcome Sterility 1 Hormone treatment • This treatment is suitable for individuals who have imbalanced hormone. 2 Surgery • Surgery is done on women who have blockage in their Fallopian tube or men who have blockage in their sperm duct.
Hormone being injected
3 In vitro fertilisation (IVF) • This procedure is done on women who have Uterus blockage in their Fallopian tube. • This method takes out the ovum to be Fallopian tube fertilised with the sperm outside the body in a Ovary glass dish. Laparoscope surgery for blockage in • The embryo formed is then put inside the Fallopian tube uterus.
Ovum and sperm are fertilised in a glass dish to form a zygote through in vitro fertilisation Figure 4.24 Methods to overcome sterility 116
Chapter 4
Pembiakan Chapter 4: Reproduction Pengenalan kepada Penyiasatan Saintifik
Methods of Contraception There are several methods of contraception for married couples who want to plan their family as shown in Figure 4.25. Contraceptive pills
Implants
Contraceptive pills can prevent ovulation.
Video on artificial methods of contraception
Implants secrete a hormone that prevent the ovary from producing ovum.
Implant
Implant is inserted to the skin below the arm
Implants
Contraceptive pills
Use of condom
Intrauterine Contraceptive Device, IUCD
Condom is worn over the penis before copulation to prevent the sperm from entering the vagina during ejaculation.
This contraceptive device is inserted inside the woman’s uterus to prevent implantation.
IUCD
Condom
Vasectomy
Ligation Fallopian tube is cut and tied Sperm duct is cut and tied
Tied sperm duct
Tied Fallopian tube
Surgery is carried out to cut the sperm duct and the two ends are then tied to prevent the sperms from being transported to the urethra.
Surgery is carried out to cut the Fallopian tubes and the two ends are then tied to prevent the ovum from meeting the sperms.
Figure 4.25 Methods of contraception Chapter 4
117
The Importance of Practising Frequent Health Screening to Get Immediate Treatment for Problems Related to Reproductive System An individual is encouraged to do at least one health screening per year starting at the age of 40.
Why is health screening so important?
• Health screening is done as an evaluation to detect early symptoms of chronic diseases.
• Cancer involving reproductive system such as uterine cancer, cervical cancer and prostate cancer can still be treated if it is detected earlier.
• Practising health screening can reduce the risk of health problems which require high-cost treatments.
Photograph 4.8 Health screening
• The correct and safe contraceptive method can be understood by consulting a doctor during the health screening.
4.6
21
ICS
Aim: To debate on the abuse of knowledge regarding contraception methods and the effects to society. Instruction 1. In group, organise a debate competition between the proposition and the opposition regarding the motion below. “Birth control should be allowed in our country” 2. Find the information on the motion using reference materials such as magazines, flyers and the Internet to prepare for the debate. 3. Carry out the debate. 4. After the debate, summarise the main points from the speeches.
118
Chapter 4
Pembiakan Chapter 4: Reproduction Pengenalan kepada Penyiasatan Saintifik
4.6 1. List four factors of sterility in males and females. 2. What methods can be used to help a married couple to have a child if (a) the husband is sterile? (b) the wife has a blockage in her Fallopian tubes? 3. Explain vasectomy and ligation method. 4. What is meant by test tube baby? 5. State two importance of practising frequent health screening for an individual. 6. Abortion should not be the method to prevent birth. Give your opinion.
4.7
Plant Reproduction
Let’s learn • • • • •
Communicate about the structure and function of each part of a flower. Justify the pollination process. Describe the process of fertilisation and explain the formation of seeds and fruits in plants. Describe the germination process of a seed. Solve problems if germination does not occur.
J
ust like any other living things, plants also need to reproduce to ensure their survival. All living things will undergo growth and finally die. They have to be replaced with new organisms.
I bear fruits to prevent my species from going extinct.
If I fail to bear fruits, I don’t know what will happen to my next generation.
Chapter 4
119
Structure and Function of Each Part of a Flower Have you ever observed a flower? If you remove the petals, what are the other parts of the flower that you can observe? What are their names and functions? Figure 4.26 shows a longitudinal section of a flower and its function.
Stamen
Anther Stigma
Filament
Stamen: Male reproductive organ. Style
Petal: Usually colourful to attract insects and animals.
Petal Pistil
Pistil: Female reproductive organ.
Sepal: Usually green in colour and it protects the flower during the bud stage.
Sepal
Ovary Ovule
Figure 4.26 Longitudinal section of a flower and its functions
4.7 Aim: To examine different types of flowers to identify their structures and functions. Instruction 1. Find a few types of flowers in your school compound. 2. Dissect your specimens. Identify the following parts: (a) flower petal and sepal. (b) male reproductive organ. (c) female reproductive organ. 3. Draw and label the structures of the flowers that you have observed. 4. Display your drawing with labels on the notice board in your class.
120
Chapter 4
Pembiakan Chapter 4: Reproduction Pengenalan kepada Penyiasatan Saintifik
Pollination There are two types of flowers, bisexual and unisexual flowers. Most flowers are bisexual because they have both male (stamen) and female (pistil) reproductive organs in the same flower. Unisexual flowers are incomplete because they only have stamen or pistil. Table 4.5 Types of flower
Unisexual
Stamen Anther Filament
Male flower
Bisexual
Stigma Anther Style Stamen Pistil Ovary Filament Ovule Sepal Sepal
Petal
Petal Stigma Style Pistil Ovary Ovule
Female flower
Some examples of unisexual flowers are corn flower and papaya flower, in which only female flowers can produce fruits and seeds. Can you state another example of a unisexual flower? Papaya plant
Male flower
Female flower
Corn plant
Male flower
Female flower
Photograph 4.10 Examples of unisexual flowers Chapter 4
121
The pollination is the process of transferring matured pollen grains from anther to stigma. The matured anther will burst and spread the pollen grains. Some pollen grains might fall on soil and some are brought by pollinating agents to the stigma of a flower. Pollination is divided into two, self-pollination and cross-pollination as shown in Figure 4.27. Types of pollination
Cross-pollination
Self-pollination
Pollen grains Pollen grains
Pollen grains are transferred to the stigma of another flower on the same plant
122
Chapter 4
Pollen grains are transferred to the stigma of the same flower
Pollen grains are transferred to the stigma of another flower on a different plant of the same species
Pembiakan Chapter 4: Reproduction Pengenalan kepada Penyiasatan Saintifik Figure 4.27 Types of pollination
4.8 Aim: To gather and interpret data on pollination Instruction 1. Surf the Internet and watch an animation on pollination of a flowering plant. 2. Gather the information obtained from websites and other references. 3. Discuss the following matter: (a) definition of pollination and types of pollination. (b) comparison between self-pollination and cross-pollination. (c) advantages of cross-pollination. (d) application of cross-pollination in agriculture. 4. Present your discussion in your class.
Pollinating Agents How do pollen grains from a plant get transferred from the anther to the stigma of the flower? Figure 4.28 shows the transferring process carried out by a pollinating agent. Stigma
grains from the 1 Pollen anther of flower A sticks
on the body or legs of the insect.
Anther Flower B
Flower A
pollen grains 2 The carried by the insect
are transferred to the stigma of flower B.
Figure 4.28 The transferring process of pollen grains by a pollinating agent
Wind, animals, and insects are pollinating agents that help in the transferring process (Figure 4.29). What are the characteristics of the flower that determine its pollinating agent? Chapter 4
123
1
Animals and insects
• Pollen grains usually stick on the beak or body of the animal. • When an insect lands on a flower to suck its nectar, pollen grains will stick to its furry feet and body. • The characteristics of animal-pollinated and insect-pollinated flowers: ◆ have big and colourful petals ◆ have nectar and smell nice ◆ produce rough and sticky pollen grains • Examples of animal-pollinated flowers and insect-pollinated flowers are durian, rambutan, papaya, hibiscus, sunflower and rose.
2 Wind • Light pollen grains are blown by the wind and reaches the stigma of another flower. • The characteristics of wind-pollinated flowers: ◆ have white or pale petals ◆ have a long and furry stigma ◆ have plenty of small, smooth and light pollen grains ◆ have a long filament and style • Examples of wind-pollinated flowers are corn, grass and paddy. Figure 4.29 Pollinating agents and the characteristics of the flowers they pollinate
124
Chapter 4
Pembiakan Chapter 4: Reproduction Pengenalan kepada Penyiasatan Saintifik
The Advantages of Cross-Pollination Cross-pollination combines genetic materials from two parent plants of the same species. Cross-pollination has many advantages.
Photograph 4.10 Cross-pollination ensures cross products inherit good characteristics from both parents.
Healthier plants which can adapt better to changes in the environment
New plants that are more resistant to pests and diseases
The advantages of cross-pollination
My Malaysia
New varieties of plants
Agencies involved in research to improve the quality and quantity of Malaysian agriculture products are: • Malaysia Agriculture Research and Development Institute (MARDI) • Malaysia Palm Oil Board (MPOB)
Good quality seeds
Figure 4.30 The advantages of cross-pollination
The Innovation of Cross-Pollination in Agriculture In Malaysia, the application of cross-pollination in agriculture is not something new. This technique has been widely used to produce better crops with higher quality. Examples of innovation of cross pollination in agriculture are summarised in Table 4.6.
Chapter 4
125
Table 4.6 Innovation of cross-pollination in agriculture
Plant
Parent plants
Hybrid plant
Pisifera and Dura
Tenera
Subang 6 and Sunrise Solo
Eksotika
Sweeter fruits and more flesh
Corn
Sweet corns from Taiwan and Mexico
Masmadu
Sweeter and bigger fruits and higher resistance towards diseases and drought
Paddy
Siam-29 and Pebifun
Malinja
Palm oil Papaya
Characteristics of hybrid plant More fruits and flesh, thinner shell
More harvest and ripe faster
Fertilisation Process After pollination, fertilisation will occur. The male gamete carried by the pollen fuses with the female gamete in the ovule. How does this process occur? Figure 4.31 shows the process of fertilisation between male and female gametes in plants.
Pollen grain Pollen tube
1
Male gamete Pollen grains fall onto stigma.
2 Ovary Ovule
3
Pollen tube carrying male gamete grows towards the ovary.
Pollen tube Pollen tube
Ovary
After the pollen tube penetrates the ovule, the male gamete fuses with the female gamete (fertilisation).
Ovule
Ovary Ovule
Figure 4.31 Fertilisation of male and female gametes in plants 126
Chapter 4
Male gamete
Pembiakan Chapter 4: Reproduction Pengenalan kepada Penyiasatan Saintifik
Structures of a Seed and Their Functions After fertilisation, the ovule grows inside the ovary and then develops into seeds. A seed is made up of an embryo wrapped in a seed coat or testa. The other parts of the flower will wither and fall. Seeds are divided into two which are monocotyledonous and dicotyledonous. Figure 4.32 and Figure 4.33 show the structure of monocotyledonous and dicotyledonous seeds.
B
Nowadays, many seedless fruits are produced. Justify this action.
Testa
Testa Hilum
Seed coat Endosperm Cotyledon Plumule Radicle
Seed coat
Plumule Radicle Embryo Cotyledon
Micropyle
Radicle (a) Front view
(b) Longitudinal section
Figure 4.32 The structure of a green bean (dicotyledonous)
(a) Front view
(b) Longitudinal section
Figure 4.33 The structure of a maize grain (monocotyledonous)
Table 4.7 shows the structure and function of a seed.
Table 4.7 The structure and functions of a seed
Part External
Embryo
Structure
Function
Testa
Protects the seed
Hilum
Place where the seed sticks to the fruit
Micropyle
Small hole to allow air and water to enter the seed
Plumule
Part of the embryo which develops into a new shoot
Radicle
Part of the embryo which develops into the root
Cotyledon / Endosperm
Stores and provides food for the seed
Photograph 4.11 Sprouting seeds
Chapter 4
127
Germination of Seeds How does the shape of a germinating seed change in terms of the growth of the radicle, plumule and the condition of the cotyledon? During germination, the testa bursts and the radicle starts to appear and grow downwards into the soil to form root. Meanwhile, the plumule grows upwards to form a new shoot. Certain cotyledons are carried out of the soil and this is known as epigeal germination (Figure 4.34). There are also cotyledons that remain in the soil during germination. This germination is known as hypogeal germination (Figure 4.35). Leaf and stem from plumule
Plumule Soil surface
Cotyledon
Cotyledon
Root
Radicle
Figure 4.34 Epigeal germination
Shoot
Soil surface
Plumule
Cotyledon
Plumule Cotyledon Radicle Root
Figure 4.35 Hypogeal germination
128
Chapter 4
Pembiakan Chapter 4: Reproduction Pengenalan kepada Penyiasatan Saintifik
The Conditions Required for Germination of Seeds What are the conditions required by seed to germinate? Let us carry out Experiment 4.1 to determine the required conditions for seed germination. Seeds will germinate if conditions are suitable as in Figure 4.39.
I need these conditions to germinate!
Water Air Suitable temperature
Figure 4.39 The required conditions for germination of seeds
Experiment
4.1
Problem statement: Are air, water and suitable temperature necessary for seeds to germinate? Hypothesis: Seed needs air, water and suitable temperature to germinate Aim: To determine the required conditions for the germination of seeds Variables Manipulated variable: Germination conditions Responding variable: Seed germination Constant variable: Type of seed Materials and apparatus: Boiling tube, cotton wool, water, cooking oil, sugar paper, green beans, refrigerator Procedure 1. Prepare four boiling tubes labelled A, B, C and D as shown in Figure 4.37 (a) and 4.37 (b). A B Sugar paper Seeds Wet cotton wool (a) Room temperature
Dry cotton wool (b) Room temperature
Figure 4.37 (a) Chapter 4
129
C
D Sugar paper Cooking oil Cooled boiled water Seeds
(c) Room temperature
Wet cotton wool
(d) Temperature: 10°C
Figure 4.37 (b)
2. Test tube A, B and C are put in the laboratory while test tube D is put inside a refrigerator. 3. Observe all the seeds after five days for each of the boiling tube. 4. Record your observation in a table. Result Test tube
Presence of Water
Air
Suitable temperature
Seed germination (Germinate/ Does not germinate)
A B C D Conclusion Is the hypothesis accepted? Questions 1. How do you set up a control experiment? 2. What is the purpose of using cooking oil in this experiment?
4.7 1. What is the function of flower petal in plant reproduction? 2. Why is sepal different from petals? 3. Why do some papayas bloom but not bear fruits? 4. Explain the function of the following parts of a flower in plant reproduction. (a) Stigma (b) Style (c) Anther 5. State the differences between a wind-pollinated flower and an insect-pollinated flower. 130
Chapter 4
Ovum
Sperm
Baby
Foetus
Embryo
Zygote
Fertilisation
Female reproductive system
Male reproductive system
Human
Sexual
In vitro fertilisation
Surgery
Hormone treatment
Sterility
Pistil
Stamen
Ligation
Vasectomy
Intrauterine contraceptive device (IUCD)
Condom
Female gamete
Chapter 4
Germination of seed
Formation of seed and fruit
Fertilisation
Male gamete
Ovule
Female part
Vegetative reproduction
Regeneration
Spore formation
Budding
Binary fission
Cross-pollination Asexual Animal and insect
Wind
Self-pollination
Types of pollination
Flowering plant Pollinating agent
Male part
Plant reproductive system
Contraceptive pills Pollen grain Implant
Contraception method
Importance of research in reproductive system
Reproduction
Pembiakan Chapter 4: Reproduction Pengenalan kepada Penyiasatan Saintifik
131
After learning this chapter, you are able to: 4.1 Sexual and Asexual Reproduction Compare and contrast sexual and asexual reproduction in animals and plants. Reason the importance of reproduction. Be grateful for the ability to reproduce and the continuation of life as a gift from God. 4.2 Human Reproductive System Identify the structures and function of the male and female reproductive systems. Communicate about the physical changes that occur during puberty. Compare and contrast male gamete with the female gamete in the reproductive system. 4.3 Menstrual Cycle Communicate about the menstrual cycle and the sequence of changes in the uterus lining during menstruation. Relate the fertile phase of the menstrual cycle to the process of fertilisation. Justify the importance of personal hygiene during menstruation. 4.4 Fertilisation and Pregnancy Communicate about the process of fertilisation and the implantation of embryo. Justify the importance and functions of placenta and umbilical cord. Describe the development of a zygote into an embryo and subsequently into foetus during pregnancy until birth. 4.5 Factors Affecting the Development of a Foetus and Baby Relate the importance of taking nutritious food during pregnancy to the health of both mother and foetus. Justify the importance of avoiding the intake of harmful substances to the foetus. Justify the benefits of breastfeeding compared to formula milk on the infant’s development. Realise that every living creature has a right to live even if its in the womb. 4.6 Infertility and Contraception Communicate the meaning of infertility and how to overcome them. Differentiate methods of contraception. Realise the importance of practising frequent health screening and to get immediate treatment for problems related to the reproductive system. 4.7 Plants Reproduction Communicate about the structure and function of each part of a flower. Justify the pollination process. Describe the process of fertilisation and explain the formation of seeds and fruits in plants. Describe the germination process of a seed. Solve problems if germination does not occur. 132
Chapter 4
Pembiakan Chapter 4: Reproduction Pengenalan kepada Penyiasatan Saintifik
Summative Practice
4
1. The image of a foetus can be seen through ultrasound imaging. Ultrasound is considered safe for the mother and the foetus. Figure 1 shows the foetus image formed after 12 weeks of pregnancy. Figure 1
(a) Based on Figure 1, the foetus is in a fluid. What is the name of the fluid? (b) What is the function of the fluid you mentioned in 1(a)? (c) Which part connects the foetus and the mother’s uterus and how does the foetus obtain its food and oxygen? (d) When the features of the foetus is completely formed, a baby will be born. Explain the
birth process.
Thickness of uterine lining
2. Figure 2 shows the changes in the thickness of the uterine lining during the menstrual cycle.
5
(a) Based on Figure 2, predict (b)
14
18
Figure 2
28
5
Day
(i) when menstruation phase occurs; (ii) when ovulation occurs for the woman? If the woman has sexual intercourse on the 13th day of her menstrual cycle, is there any possibility of her getting pregnant?
3. Development in science and technology has helped married couples to plan their family and overcome sterility problems. (a) Explain any two temporary contraceptive methods. (b) Selling condoms openly has been said to contribute to social problems in a society. Do you agree with this statement? Give your opinion.
Chapter 4
133
4. An experiment was done by a group of researchers to study the effect of nicotine on sperm production. Sixty rats were divided into three groups. The first group was not given any nicotine, the second group was given a low dose of nicotine every day and the third group was given a high dose of nicotine every day. This research was done for 30 days. Then, the number of abnormal sperms produced by each rat was recorded in Table 1. Table 1
Nicotine dose Percentage of abnormal sperm
None 7
Low 20
High 33
(a) Based on Table 1, draw a bar chart. (b) What are the two variables that must be kept constant in this experiment? (c) What is the conclusion that can be made by the researchers from this experiment? (d) Suggest one reason why the first group of rats were not given any nicotine. (e) State one effect of nicotine on a baby who is born to a mother who smokes during pregnancy. What is the best solution for a mother who is addicted to nicotine? 5. Figure 3 shows the general structure of a flower. (a) State the structure that forms (i) the female reproductive organ. (ii) the male reproductive organ. (b) If we go to a flower park, a lot of insects are seen flying around flowers.
Figure 3
(i) What are the characteristics of the flowers that attract the insects?
(ii) How do insects help in the plant reproduction process?
6. Sterility is always the main problem for newly married couples and it is caused by various factors. Is it true that sterility only happens to women? Give your opinion. 7. A married couple has been married for 12 years, but they still do not have a child. (a) From a medical perspective, what is your assumption on why they still do not have a child? (b) Based on your answer in 7(a), suggest one method to overcome their problem. Explain the benefits of the method.
134
Chapter 4
Jirim 5: Matter Chapter Pengenalan kepada Penyiasatan Saintifik
3
Exploration of Elements in Nature
water to melt, m a e r c ice r and causes hot wate m o r f What to form the air? cule, vapour oat in m mole fl o r f to n m o ballo ates ato und? ifferenti d t mpo a h W from co d control air t n e m ent an and ele we prev n a c w Ho n? pollutio
Chapter Bab 5
135
Chapter
5
Matter
Why do solids, liquids and gases have different physical properties? How does smell spread in the air? What are the examples of changes in the state of matter in our life?
Let’s Study: Matter in Nature Three States of Matter 136
Chapter 5
Jirim 5: Matter Chapter Pengenalan kepada Penyiasatan Saintifik
SCIENCE BULLETIN
BEE ATTACKS
swarm ave you ever been attacked by a n one whe that ise real of bees? Do you a r, late utes min few bee starts to attack, a The ? too ck atta to t swarm of bees will star ase a kind first bee that attacks you will rele es a duc pro ch whi of chemical substance s. smell to alert other bee
H
Gas
al How does the smell of the chemic cted dete get and air substance spread in the ticles through diffusion. The odour par by other bees? The smell spreads ctions. dire s iou var in ly in the air random of the chemical substance move s iou var from ce stan the chemical sub Therefore, other bees can smell directions.
Liquid
Solid
[Gas, Liquid, Solid]
Matter Particle Extraction Melting Boiling Solubility Solid
Liquid Gas Diffusion Evaporation Condensation Freezing Sublimation Chapter Bab 5
137
5.1
Matter in Nature
Let’s learn • • • •
State that almost everything that exists in nature is matter. Prove that living things and non-living things have mass and occupy space. Differentiate the physical properties and chemical properties of matter. Classify materials by the different characteristics.
C
an you list all the things that you can see in Photograph 5.1? Do they have mass and occupy space? Do you know that all the things you have listed are matter? Matter can be defined as a substance that has mass and occupies space.
Photograph 5.1 Matter
All living things including humans, plants and animals are classified as matter. Non-living things such as water, soil, rocks and air are also matter. Can you state examples of non-matter? Let us do Activity 5.1 to show that almost every living and non-living thing in nature is a matter.
138
Chapter 5
B
1. Is there any object that has mass but does not occupy space? 2. Is there any object that occupies space but does not have mass?
Jirim 5: Matter Chapter Pengenalan kepada Penyiasatan Saintifik
5.1 A Aim: To show that living and non-living things have mass and occupy space Materials and apparatus: Lever balance, beaker, soil, water, bean sprouts Instruction 1. Weigh an empty beaker with a lever balance. Record its mass. 2. Fill half of the beaker with soil. Does the soil occupy space inside the beaker? 3. Weigh the beaker with the soil by using the lever balance as shown in Figure 5.1. Does soil have mass? 4. Repeat steps 1 – 3 by replacing soil with water and bean sprouts. Beaker Soil Lever balance Pointer
5. Complete the table below. Material
Figure 5.1 Set-up of apparatus
Living/ non-living things
Mass (g)
Occupy space
Soil Water Bean sprouts Questions 1. Classify the materials in this activity into living and non-living things. 2. Are soil, water and bean sprouts matter? Explain your answer. 3. Give five other examples of things that are matter.
Chapter Bab 5
139
B Aim: To show that air has mass and occupies space Materials and apparatus: Balloons, pin, rope, cellophane tape, wooden rod. Instruction 1. Blow up two balloons and make sure they are of the same size. 2. Stick a piece of cellophane tape on one of the balloons. 3. Attach the balloons to a wooden rod. Balance both balloons (Figure 5.2). 4. Use a pin to prick the balloon through the cellophane tape. Observe any changes.
Rope
Wooden rod
Balloon Cellophane tape
Figure 5.2
Questions 1. Did the balloons expand when you blew them up? Why? 2. What happened to the wooden rod when one of the balloons was pricked with the pin? 3. Why do we stick a cellophane tape to the balloon that we want to prick? Conclusion What conclusion can you make from these activities?
Physical Properties of Matter Every matter has its own physical properties. What is meant by physical properties? Physical properties are the properties that can be identified by using our five senses or measuring tools. Physical properties of matter depend on the type of material it is made of. Look at Photograph 5.2. What is the main material to make a kayak? Can you state the physical properties of the kayak? Figure 5.3 shows some examples of physical properties of matter.
Photograph 5.2 Kayak 140
Chapter 5
Jirim 5: Matter Chapter Pengenalan kepada Penyiasatan Saintifik Different liquids have different boiling points. The boiling point of water is 100°C. Sugar can dissolve in coffee.
The handle is made of heat insulator such as plastic.
The pan is made of heat conductor such as steel.
Figure 5.3 Physical properties of matter
The melting point of ice is the temperature at which ice changes into liquid at a certain pressure.
Chemical Properties of Matter Besides physical properties, each matter has its own chemical properties. What is meant by chemical properties? Chemical properties are the properties of a substance that become evident when it changes to a new substance. Chemical properties depend on the reaction that occurs upon the substances. Figure 5.4 shows some examples of chemical properties of matter. The new substance produced from the chemical reaction has a different composition from its original substance.
Rusting occurs on iron when it is exposed to water and air.
Petrol is a flammable matter.
Figure 5.4 Chemical properties of matter Chapter Bab 5
141
Let us carry out Activity 5.2 to differentiate between physical properties and chemical properties of matter.
5.2 Aim: To differentiate physical and chemical properties of matter Instruction 1. Work in groups. 2. Identify each of the situation below whether it is a chemical or physical property of matter. Then, state the process involved.
Ice cream melts when exposed to a certain temperature Water boils at 100°C
Iron spoon becomes hot when it is put in a cup of hot coffee
Iron key rusts when it is exposed to air and water
3. Present your discussion in front of your friends and teacher.
Paper burns when it is lit
Medicine tablet dissolves in water
How Can We Classify Materials by their Different Characteristics? Seawater is salty because of the salt content in it. What are the differences between the properties of salt and seawater? Salt and seawater have different boiling points. Water evaporates into water vapour as its boiling point is lower than salt. Eventually, only the salt crystals are left behind. We can classify various materials by the following characteristics: Density Melting point Boiling point Solubility
Photograph 5.3 Salt is separated from seawater through evaporation 142
Chapter 5
Jirim 5: Matter Chapter Pengenalan kepada Penyiasatan Saintifik
Density
The density of a material is the mass per unit volume of that material. Density determines the ability of a material to float or sink in water. A material that has a lower density will float, while a material that has a higher density will sink. For example, oil has a lower density which causes it to float on water. Table 5.1 shows some examples of classification of substances by density.
Oil Water
Photograph 5.4 The layers of oil and water Table 5.1 Classification of substances by density
Substance Mixture of glycerol and water Mixture of petrol and mercury Mixture of sand and water Mixture of oil and cork
Higher density Glycerol Mercury Sand Oil
Lower density Water Petrol Water Cork
Melting Point and Boiling Point Melting point is the temperature at which a substance changes from solid to liquid. Boiling point is the temperature at which a substance changes from liquid to gas. Matter can also be classified by its melting and boiling point.
Ice melts at 0°C
Iron melts at 1536°C
Water boils at 100°C
Photograph 5.5 Melting and boiling point of various substances
Melting and boiling points of some substances are listed in Table 5.2. Table 5.2 Melting and boiling points of various substances
Substance Water Alcohol Copper Oxygen
Melting point (°C) 0 -117 1085 -218
Boiling point (°C) 100 78 2562 -183 Chapter Bab 5
143
Solubility
Sugar
Solubility is the ability of a substance to dissolve in a given amount of solvent to form a solution. The solubility of a substance depends on the physical and chemical Coffee properties of its solute and solvent. As different substances have different solubility, matter can also be classified by its solubility. For example, we dissolve sugar (solute) in a cup of coffee (solvent) to drink. Photograph 5.6 Examples of solute
and solvent
5.3 Aim: To classify materials by the different characteristics from various physical properties Instruction 1. Work in groups. 2. Classify each of the following materials according to its density compared to water and solubility in water. Material
Density compared to water
Solubility in water
(a) Salt (b) Twig (c) Cooking oil (d) Cork (e) Glass marble (f) Sand (g) Sugar crystals (h) Cocoa powder 3. Record your findings in your practical book.
5.1 1. List five examples of matter around you. 2. What are two characteristics of matter? 3. Are all living things matter? Explain your opinion. 4. Sarah turns over an empty beaker into a basin of water. She finds that the water cannot flow into the beaker. What can you conclude from her observation? 5. State the difference between physical and chemical properties.
144
Chapter 5
Basin Water Beaker
Jirim 5: Matter Chapter Pengenalan kepada Penyiasatan Saintifik
5.2
Three States of Matter
Let’s learn • Generalise that matter consists of particles. • Compare and contrast three states of matter based on the kinetic theory in terms of the arrangement and movement of particles. • Use space-time relationships to compare rate of diffusion in three states of matter. • Describe the change in state of matter, in terms of movement of particles caused by the absorption and the release of heat, based on kinetic theory. • Conclude that temperature remains constant during melting/ freezing and boiling. • Conclude that mass remains constant during physical changes. • Explain with examples the changes of the state of matter in daily life.
M
atter is made up of discrete particles. These particles are so tiny and cannot be seen with our naked eye or even by using a light microscope. It can only be seen through an electron microscope. Let’s do Activity 5.4 to understand the concept of matter which is made up of small and discrete particles.
5.4 Aim: To show that matter is made up of small and discrete particles Materials and apparatus: Copper(II) sulphate crystal, water, beaker Instruction 1. Pour 50 ml of water into a beaker. 2. Put a few crystals of copper(II) sulphate into the beaker of water. Observe the changes in colour of the solution. 3. Add another 50 ml of water into the beaker and record your observation. Questions 1. What can you observe when more water is added into the beaker? Explain your observation. 2. What conclusion can be made from this activity?
Water
Copper(II) sulphate crystals
Figure 5.5
Science Career Kinetic theory of matter states that matter is made up of constantly moving small and discrete particles.
Figure 5.6 Kinetic theory of matter
Material scientist is a person who studies the composition and characteristics of matter that is used in agricultural, industrial and medical fields.
Chapter Bab 5
145
Particles of matter always collide with one another. When heat is supplied, the particles will move faster. On the other hand, the particles will move slower when it is cooled. Matter exists in three different states, solid, liquid and gas. Examples of the three states of matter are shown in Figure 5.7.
Solid Ceramic cup is solid
Three states of matter idahoptv.org/ sciencetrek/topics/ matter/facts.cfm Video on substances and their states
Liquid
Gas
Honey is liquid
Vapour produced from hot tea is gas
Figure 5.7 The three states of matter
Water is the only substance in this nature that exists in all three states naturally. Water is in a liquid state at room temperature. When it is frozen, water changes to ice. Meanwhile, water that is heated at 100°C will change to steam.
Ice is water in solid state
146
Chapter 5
Water exists as a liquid at room temperature
Steam is water in gas state
Jirim 5: Matter Chapter Pengenalan kepada Penyiasatan Saintifik Table 5.3 Comparison of characteristics of three states of the matter
State of matter Characteristic
Solid
Liquid
Gas
Shape
Fixed shape
Takes the shape of the container
Takes the shape of the container
Mass
Fixed mass
Fixed mass
No fixed mass
Volume
Fixed volume
Fixed volume
Follows the volume of the container
Compressibility
Incompressible
Difficult to compress
Compressible Science Exploration
GAS Space between particles: Large Particles arrangement: Very loose Particles movement: Move randomly and collide with one another
The Sun is not categorised as a solid nor gas. The Sun is in a state called plasma.
LIQUID Space between particles: Moderate Particles arrangement: Close Particles movement: Move freely and collide with one another
SOLID Space between particles: Small Particles arrangement: Very close Particles movement: Vibrate in a fixed position
Wood or iron are used to build bridges because it has a compact arrangement and a fixed shape.
Figure 5.8 Comparison of characteristics of the three states of matter Chapter Bab 5
147
5.5 Aim: To prepare a visual presentation on the three states of matter Instruction 1. Work in groups. 2. Each group has to choose one state of matter that represents their group. 3. Prepare a PowerPoint presentation to explain about the matter that you have chosen. Your presentation must include the following aspects: (a) physical properties of the matter (b) arrangement and movement of particles in the matter (c) relationship between the arrangement and movement of the particles in the matter to the physical properties of the matter. Question 1. List other examples of matter.
Diffusion Rate in Three States of Matter Have you ever wondered why a spray of perfume can be detected from afar? The smell spreads because its small discrete particles travel with the air particles. These particles move randomly in various directions which cause the smell of perfume to spread. We could say that diffusion has just occurred. Diffusion is a process in which the particles of substances diffuse from a high concentration area to a low concentration area.
Perfume particle
Air particle
148
Chapter 5
Figure 5.9 Diffusion of perfume
B
What is the purpose of heating aromatic oil as shown in the photograph below?
Jirim 5: Matter Chapter Pengenalan kepada Penyiasatan Saintifik
Is there a difference in the rate of diffusion in solids, liquids and gases? Let us carry out Experiment 5.1 to compare the rate of diffusion between the different states of matter.
Experiment
5.1
Problem statement: What is the difference in the rate of diffusion between solids and liquids? Hypothesis: The rate of diffusion is low in a solid, but high in a liquid. Aim: To determine the rate of diffusion of copper(II) sulphate in two states of matter. Variables (a) Constant variable: Temperature (b) Manipulated variable: Diffusion medium (c) Responding variable: Rate of diffusion Materials and apparatus: Copper(II) sulphate crystals, colourless gel, distilled water, test tube, rubber stopper, measuring cylinder, stopwatch. Procedure A Diffusion in a solid 1. Set up the apparatus as shown in Figure 5.10. 2. Observe the changes after two days. 3. Record your observation.
Colourless gel
Copper(II) sulphate crystals
Figure 5.10
B Diffusion in a liquid 1. Put in one spatula of copper(II) sulphate crystals into a measuring cylinder filled with 50 ml of distilled water (Figure 5.11). 2. Observe the changes after 15 minutes. 3. Record your observation. Distilled water
Copper(II) sulphate crystals
Figure 5.11
Bab 5 Chapter
149
Result Activity
Observation
A B Conclusion Is the hypothesis accepted? Questions 1. State the observation for Activity A and B. 2. Compare the rate of diffusion of copper(II) sulphate in a solid and a liquid.
Figure 5.12 shows the difference between the rate of diffusion in the three states of matter. The rate of diffusion of particles in a solid, liquid and gas In a solid Before
In a liquid After
Gel (colourless) Gel turns blue
Before
In a gas After
Water Water turns blue
Before
After Air Mixture of bromine gas and air Lid
Copper(II) sulphate crystals (blue)
• The gel turns blue after a few days. • The rate of diffusion of particles in a solid is low.
Copper(II) sulphate (blue)
• Water turns blue after two hours. • The rate of diffusion of particles in a liquid is higher than in solid.
Bromine gas
• Bromine gas fills both gas jars after 15 minutes. • The rate of diffusion of particles in a gas is the highest.
Figure 5.12 The rate of diffusion of particles in a solid, liquid and gas
150
Chapter 5
Jirim 5: Matter Chapter Pengenalan kepada Penyiasatan Saintifik
Changes in the State of Matter Caused by the Absorption and the Release of Heat Based on Kinetic Theory of Matter Matter can change from one state to another when heat is absorbed or released.
There are many substances that undergo changes of matter due to absorption or release of heat in our life. What happens to the matter when heat is absorbed or released? Heating or cooling can cause changes in the state of matter. For example, when a liquid is cooled, it will release heat. The particles in the liquid will lose kinetic energy and move slower. The particles will attract one another and change into solid. The liquid undergoes the freezing process. When a solid is heated, the substance will change to liquid and lastly change to gas during the boiling process. Some substances will change directly from solid to gas. This process is called sublimation. During sublimation, the kinetic energy of the particles increases as they absorb heat until it can change directly from solid to gas.
Photograph 5.7 Heat is absorbed when water is heated
Photograph 5.8 Heat is released when water is cooled
Video of effect on heat on matter
Heated (Heat is absorbed)
Cooled (Heat is released) Solid
Liquid
Gas
Figure 5.13 The changes in the arrangement of particles when heated or cooled Chapter Bab 5
151
Sublimation Heat is absorbed
Sublimation Heat is released
Solid
e
is
He
at
Co nd
d
se
ea ed
orb
bs
sa
ing
rel
at i
as ed Bo Heat is ilin ab so g/ eva rbed por atio n
is
ez Fre
at
He
g He ltin Me
ens a rel tion
Gas
Liquid Figure 5.14 The effect of heat on matter 152
Chapter 5
Jirim 5: Matter Chapter Pengenalan kepada Penyiasatan Saintifik
Melting • Solid absorbs heat when heated. • The particles obtain energy and vibrate faster. • Heat is used to overcome the force of attraction between the particles. • Particles move freely when the temperature reaches melting point. • Solid turns into liquid. Boiling • Boiling occurs when the temperature of the liquid is equal to the boiling point of the liquid. • Liquid absorbs heat when heated. • The particles obtain energy and move faster. • Heat is used to break the bond between the liquid particles. • When the temperature reaches the boiling point, the particles move freely and randomly. • Liquid turns into gas. Evaporation • • • •
Evaporation occurs at any temperature. Liquid absorbs heat from the surroundings. The particles obtain energy and move faster. Liquid is evaporated slowly and turns into gas.
Condensation • Heat is released when gas is cooled. • The particles lose energy and move slower and closer to one another. • When the temperature is equal to or below the boiling point, gas will turn into liquid. Freezing • Liquid releases heat when it is cooled. • Particles lose energy and move slower. • Particles start to vibrate at a fixed position when they reach freezing point. • Liquid turns into solid. Sublimation • Sublimation is a process in which a solid directly turns into gas or a gas directly turns into solid.
Chapter Bab 5
153
Science in Life The bubbles are actually a thin layer of liquid containing gas. Look at the bubbles in the soup! Is it gas or liquid?
5.6 A Temperature remains constant during boiling of water Aim: To investigate whether temperature remains constant during boiling of water Materials and apparatus: Bunsen burner, tripod stand, wire gauze, beaker, thermometer, 100 ml of water, retort stand with clamp. Instruction 1. Pour 100 ml of water into a beaker. Record the initial temperature of water. 2. Heat the water. Record the temperature of water at 10 minutes interval until the temperature remains constant (Figure 5.15).
Thermometer Retort stand with clamp 100 ml water
Heat
Figure 5.15 Questions 1. Why does the temperature of water remain constant when boiling? 2. Plot a graph of temperature against time for the boiling of water.
B Mass remains unchanged during physical change Aim: To investigate whether mass remains unchanged during physical change (I) Change in mass when ice melts into water
Beaker
Materials and apparatus: Ice cubes, beaker, lever balance
Ice cubes
Instruction 1. Weigh an empty beaker. Record the mass of the empty beaker. 2. Put ice cubes into the beaker. Record the mass of the beaker filled with ice cubes. 3. Then, let the ice cubes melt. Weigh the beaker filled with water. 4. Record the mass (Figure 5.16).
Lever balance Pointer
Figure 5.16 154
Chapter 5
Jirim 5: Matter Chapter Pengenalan kepada Penyiasatan Saintifik
Question 1. Is there any difference between the mass of the ice cubes and water? (II) Change in mass when salt dissolves Materials and apparatus: Ten spatulas of fine salt, 100 ml of water, glass rod, beaker, lever balance. Instruction 1. Weigh a beaker filled with 100 ml of water. Record the mass. 2. Put ten spatulas of fine salt into the beaker. Weigh it and record its mass. 3. Stir the water until the salt dissolves. After that, weigh the solution and record the mass (Figure 5.17). Question 1. Is there any difference in mass before and after the salt dissolves?
Beaker 100 ml of water + 10 spatulas of fine salt Lever balance
Pointer
Figure 5.17
(III) Change in mass during the expansion of solid Materials and apparatus: Metal ball and ring, Bunsen burner, triple beam balance. Instruction 1. Weigh a metal ball together with its ring. Record the mass. 2. Heat the metal ball for 5 minutes. Weigh the hot metal ball with its ring. Record the mass. (Figure 5.18) Question 1. Is there any difference in the mass of the metal ball before and after heating?
Ring
Heat
Figure 5.18
When a substance is heated, the temperature will increase and when a substance is cooled, the temperature will decrease. However, the temperature will not change when it reaches freezing point, melting point and boiling point during the freezing, melting and boiling processes. Heat is absorbed or released to overcome or form the force of attraction between the particles. During these physical changes, the mass remains constant because the quantity of particles does not change when heated or cooled. The only change that occurs is the kinetic energy of the particles.
Chapter Bab 5
155
Water from wet items evaporates and becomes vapour through the process of evaporation.
Examples of change of state of matter
Freezing allows sweet creams to freeze and become ice-cream
Dry ice is used by ice-cream vendors to prevent their ice-cream from melting
Moth balls becoming smaller is an example of direct change from solid to gas through sublimation
Dew is formed when water vapour in the air condenses and becomes water droplets
Figure 5.19 Examples of change of state of matter 156
Chapter 5
Jirim 5: Matter Chapter Pengenalan kepada Penyiasatan Saintifik
5.7
21
ICS
Aim: To search for information and do a presentation Instruction 1. Work in groups. 2. Find information on two examples of change of matter for the following processes. (a) Freezing (b) Melting (c) Boiling (d) Evaporation (e) Condensation (f) Sublimation 3. Present your discussion using various forms of multimedia presentations.
5.2 1. (a) State whether the matter is a solid, liquid or gas. (i)
(ii)
(iii)
(iv)
(v)
(b) Give three other examples for each state of matter. (c) Draw a table to show the arrangement and movement of particles for each state of matter. 2. How does the smell of cooking spread all over the house? 3. State the kinetic theory of matter. 4. Why is the temperature constant during the boiling of water? 5. In four season countries, the temperature may drop till below 0ºC during the peak of winter. Why does the surface of the river or lake freeze?
Chapter Bab 5
157
158
Chapter 5
Has mass
Density
Heat conductivity
Solubility
Melting point and boiling point
Physical properties
Solubility
Moves and collides with each other
Melting Boiling Freezing Evaporation Condensation Sublimation
Change of state of matter
Vibrate at its own position
Moves freely and randomly, collides with each other
Arranged loosely
Arranged closely
Arranged very closely
Melting point Boiling point
Gas
Liquid
Solid
State of matter
Density
Classification of materials by characteristic
Flammability
Rusting
Chemical properties
Properties of matter
Occupies space
Definition of matter
Matter
Jirim 5: Matter Chapter Pengenalan kepada Penyiasatan Saintifik
After learning this chapter, you are able to: 5.1 Matter in Nature State that almost everything that exists in nature is matter. Prove that living things and non-living things have mass and occupy space. Differentiate the physical properties and chemical properties of matter. Classify materials by their different characteristics. 5.2 Three States of Matter Generalise that matter consists of particles. Compare and contrast three states of matter based on the kinetic theory in terms of the arrangement and movement of particles. Use space-time relationship to compare rate of diffusion in three states of matter. Describe the change in state of matter in terms of movement of particles caused by the absorption and the release of heat based on kinetic theory. Conclude that temperature remains constant during melting / freezing and boiling. Conclude that mass remains constant during physical changes. Explain with examples the changes of the state of matter in daily life.
Summative Practice
5
1. Figure 1 shows three examples of matter.
Coffee
Stones
Air inside balloon
Figure 1
(a) (b) (c)
Identify the states of matter in Figure 1. Of the three state of matter, which one has a fixed volume? What is the difference between the movement of particles in the stones and the air in the balloon? Chapter Bab 5
159
2. Umar builds a wooden tray with three partitions to separate some marbles into three sections, P, Q and R as shown in Figure 2.
P
Q
R
Marble Wooden tray
Figure 2
(a) Use the kinetic theory of matter to describe the movement of marbles in P, Q and R when Umar shakes the tray. Explain your answer. (b) Based on the properties of matter that you have learned, explain how gas is (i) compressed into liquid in a gas barrel. (ii) changed back into gas when it exits the barrel. 3. Figure 3 shows Elisya blowing soap water.
Soap bubble blower Soap bubble Soap water
Figure 3
(a) (b)
160
Determine the state of matter for the (i) air inside the soap bubbles (ii) soap bubble blower (iii) soap water What happens to the soap water when Elisya blows it harder? Give your reason.
Chapter 5
Jirim 5: Matter Chapter Pengenalan kepada Penyiasatan Saintifik
4. Tan wants to ride his bicycle to school but he finds that the tyre is flat. Tan pumps air into the tyre.
Figure 4
(a) Explain the state of the air particles inside the pumped tyre. (b) Justify Tan’s action of not pumping the tyre until it is too tight. (c) Bicycle tyres become flat when the weather is cold. Explain.
5. Ariana accidentally mixed salt and tea leaves. Suggest one way to separate the salt and tea leaves based on your knowledge of physical properties of matter.
Figure 5
6. A sailor runs out of drinking water in the middle of the sea. He cannot drink seawater directly to avoid dehydration. (a) How can you help the sailor to obtain pure water from seawater? Based on your knowledge on condensation, create an experiment that can be done using only the items in Figure 6.
Container
Plastic
Stone
Glass
Figure 6
(b) How can you prove that your experiment is a success? Suggest one simple way.
Chapter Bab 5
161
Chapter
6
Periodic Table
The smallest particle of an element is called an atom. What is the structure of an atom? Why is an atom neutral? How are the elements that exist around us arranged in the Periodic Table?
Let’s Study: Classification of Elements Mixture Compound 162
Chapter Chapter56
Jadual Berkala Chapter 6: Periodic Table Pengenalan kepada Penyiasatan Saintifik
SCIENCE BULLETIN IC TABLE
THE HISTORY OF PERIOD
Periodic Table is a le which is used by a chemist? Tab ic iod Per the n see r eve ave you The elements in this table arranged in the form of a table. nts me ele al mic che of tion compila latest form is a great evolution of this table into the The s. stic teri rac cha n mo have a few com scientists. achievement by chemists and leev, a chemist from Russia? introduced by Dimitri Mende s wa le tab this t tha w kno Do you ether with the mass of stics for 63 found elements, tog teri rac cha the te wro v lee nde He left blank spaces to be In 1869, Me arranged in the form of a table. and d car of ce pie all sm a s of the elements that the atom on had predicted the characteristic He . nts me ele nd fou be to filled with yet d by other scientists. ver, his prediction was doubte have not been found yet. Howe Mendeleev’s lled nd. This new element fulfi In 1886, germanium was fou ic Table has iod Per epted Mendeleev’s idea. The prediction. Scientists finally acc s. orie the h new findings of elements and improved over time, in line wit
H
Atom Molecule Proton Electron Neutron Element Compound Periodic Table
Non-metal Appearance Ductility Malleability Mixture Filtration Sedimentation Distillation Chromatography Chapter Bab 6
163
6.1
Classification of Elements
Let’s learn • • • • •
Conclude that all matter consists of atoms. Differentiate between atoms and molecules as well as elements and compounds. Identify the position of metal, non-metal and inert gases in the periodic table. Differentiate the characteristics of metals and non-metals. Appreciate the order of elements that exist in nature that has allowed people to organise them in the form of a table.
Y
ou have learned in Chapter 5 that all things that have mass and occupy space are matter. Matter consists of small and discrete particles which are known as atoms.
Bracelet
Hot air balloon
Figure 6.1 Arrangement of atoms in a bracelet and in a hot air balloon
An atom cannot be seen with our naked eyes because its size is too small. An atom can only be seen using an electron microscope by enlarging the atom to a million times. Imagine if an orange were an atom, it would be enlarged as big as the size of the Earth using an electron microscope (Figure 6.2).
Enlarged to 10 million times
Figure 6.2 164
Chapter 6
Science Exploration Metals and some non-metals like carbon and helium exist as atoms.
Jadual Berkala Chapter 6: Periodic Table Pengenalan kepada Penyiasatan Saintifik
Atom and Molecule An atom consists of three subatomic particles, which are protons, neutrons and electrons. Protons and neutrons are inside the nucleus of an atom, while the electrons circle around the nucleus. Electron
Proton
Particle with negative charge
Particle with positive charge Nucleus Neutron Neutral particle with no charge
You can easily remember the subatomic particles in an atom by using the acronym
Figure 6.3 The structure of an atom
PEN Proton Electron Neutron
• Johnstone Stoney created the word electron in 1891. • The word nucleus is derived from a Greek word which means little nut.
The nucleus has an overall positive charge due to the positively-charged protons in it. The number of electrons in an atom is equal to the number of protons. Thus, an atom is neutral.
Molecules are neutral particles made up of two or more atoms.
O Oxygen atom
O
O
Oxygen molecule
Figure 6.4 Oxygen atom and oxygen molecule Chapter Bab 6
165
What is an Element? An element is the simplest form of substance. It cannot be divided to two or more simpler substances. There is only one type of atom in an element. Iron, oxygen, hydrogen, aluminium, carbon and copper are elements. Oxygen is the most abundant element that exists on Earth.
Zn Zn
Zn
Zinc bucket
Zn
Zn
Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn
H
H
H
H
H
H
H
H
Oxygen tank
O O O
Hydrogen tank
H
H
Iron nails
C
C
C
C
C Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe
C
O
O
O
C
C
C
C
C C
C
C C
C
C C
C
C C
C
C C
Carbon
What is a Compound? A compound consists of two or more elements combined chemically. It is produced from a chemical reaction. Compounds can be produced in the laboratory or in a natural environment. Examples of compounds are aluminium oxide, zinc sulphide, iron chloride, sugar, water and salt. How can the components of a compound be separated? The components in a compound cannot be separated physically but it can be done chemically, for example by using electrical energy (electrolysis). Photograph 6.1 shows examples of compounds.
166
Chapter 6
C C
C
Figure 6.5 An element consists of atoms of the same type
O
O
C C
C
C
C
O O
O
C
C
C
O
C
C
O
O
O O
Jadual Berkala Chapter 6: Periodic Table Pengenalan kepada Penyiasatan Saintifik
Elements in the compound: sodium and chlorine
Sugar
Shell
Elements in the compound: calcium, carbon and oxygen Salt
Elements in the compound: carbon, hydrogen and oxygen
Photograph 6.1 Examples of compounds
Periodic Table During the 18th and 19th centuries, scientists discovered a lot of elements. They produced the Periodic Table which has been arranged in an orderly and in a systematic manner and is still being used today. As of 2016, 118 elements have been discovered.
Key: 6
Proton number
C
Metal
Symbol of element Name of element Relative atomic mass
Carbon 12
Semi-metal
Inert gases
Non-metal
1 1
18 2
H
2
Hydrogen 1 3
Li
4
Be
Lithium 7 11
Na Sodium 23
19
K
Rb
Rubidium 85.5 55
12
Cs Fr
Francium
13
Mg
20
Ca
3 21
40
Sr
39
Strontium 88 56
Ba Barium 137
88
Ra
Sc
4 22
Scandium 45
Calcium 38
Y
Yttrium 89 57 – 71
Actinoids
40
Zr
5 23
V
Vanadium 51 41
Nb
Zirconium 91 72
Hf
Hafnium 178.5 104
Niobium 93 73
Ta
Tantalum 181 105
Db
Rf
Dubnium
Rutherfordium
57
Lanthanoids
Ti
Titanium 48
Lanthanoids 89 – 103
Radium
La
58
Lanthanum 139 89
Actinoids
14 6
C
Boron 11
Magnesium 24
Caesium 133 87
B
Beryllium 9
Potassium 39 37
13 5
Ac
Actinium
Ce Cerium 140
90
Th
Thorium 232
6 24
Cr
Chromium 52 42
Mo
Moybdenum 96 74
W
7 25
43
Sg
Pr
Pa
Protactinum 231
Fe
Re Bh
44
Nd
Neodymium 144 92
U
Uranium 238
27
Ru
Os
Co
45
Hs
Rh
Pm
Promethium 93
Np
Neptunium
Ni
Ir
Mt
Meitnerium
62
Sm
Samarium 150 94
Pu
Plutonium
11 29
Cu
Nickle 59 46
Pd
47
Ag
Pt
Au
Ds
63
Eu
Europium 152 95
Am
Americium
Zn
48
Rg
64
Gd
Cm Curium
Ga
Cd
Gallium 70
49
Hg
Cn
Copernicium
65
Tb
Terbium 159 97
Bk
Berkelium
14
Si
In
Silicon 28 32
Ge
50
Sn
Tl
Pb
Thallium 204 113
Uut
Ununtrium
66
Dy Cf
Californium
Fl
Flerovium
67
Ho
P
33
Es
Einsteinium
16
As
51
S
34
Sb Bi
Uup
Ununpentium
68
Er
Erbium 167 100
Fm
Fermium
Se
52
Te
Cl
35
Po Lv
Livermorium
69
Tm Thulium 169
101
Md
Mendelevium
Neon 20
18
Ar
Br
Argon 40 36
Bromine 80 53
I
Kr
Krypton 84 54
Xe
Iodine 127 85
Polonium 210 116
Ne
Chlorine 35.5
Tellurium 128 84
Bismuth 209 115
17
Selenium 79
Antimony 122 83
F
Helium 4
10
Fluorine 19
Sulphur 32
Arsenic 75
Holmium 165 99
O
He
17 9
Oxygen 16
Phospharos 31
Lead 207
114
Dysprosium 162 98
15
Tin 119
82
16 8
Nitrogen 14
Germanium 73
Indium 115 81
Mercury 201
Gadolinium 157 96
31
Cadmium 112 80
112
Roentgenium
Al
N
Carbon 12
Aluminium 27
Zinc 65
Gold 197
111
Darmstadtium
30
Silver 108
79
Platinum 195 110
12
Copper 64
Paladium 106 78
Iridium 192 109
Hassium
61
28
Rhodium 103 77
Osmium 190 108
10
Cobalt 59
Ruthenium 101 76
Bohrium
60
9
Iron 56
Rhenium 186 107
Praseodymium 141 91
Tc
Technetium 98 75
Seaborgium
59
26
Manganese 55
Tungsten 184 106
Mn
8
15 7
At
Xenon 131
86
Astatine 210 117
Rn Radon 222
118
Uus Uuo
Ununseptium
70
Yb
Ytterbium 173 102
No
Nobelium
Ununoctium
71
Lu
Lutetium 175 103
Lr
Lawrencium
Figure 6.6 The Periodic Table Chapter Bab 6
167
In the past, some elements were named according to the substances they produced. The names end with ‘gen’ (abbreviated from ‘generator’). Hence, hydrogen means ‘water generator’ and nitrogen means ‘nitric acid generator’. Today, the names of new elements have to be approved by the International Union of Pure and Applied Chemistry (IUPAC). Most of the elements were named after the person who discovered them, the place of discovery and the name of well-known scientists (Table 6.1). However, elements 113, 115, 117 and 118 have not been officially named yet. Figure 6.7 Research of elements Table 6.1 The new elements discovered by scientists
Element
Name/ Symbol
104 106 107 109 110 111
Rutherfordium (Rf) Seaborgium (Sg) Bohrium (Bh) Meitnerium (Mt) Darmstadtium (Ds) Roentgenium (Rg)
Year of discovery 1969 1974 1976 1982 1994 1994
112
Copernicium (Cn)
1996
113 115 117 118
Ununtrium (Uut) Ununpentium (Uup) Ununseptium (Uus) Ununoctium (Uuo)
2003 2004 2010 2006
168
Chapter 6
Named after Ernest Rutherford, nuclear physicist Glenn Seaborg, chemist Niels Bohr, physicist Lise Meitner, physicist Darmstadt, Germany (place of discovery) Wilhelm Roentgen, physicist Named after Nicolaus Copernicus, physicist, but discovered by Sigurd Hofmann Not officially named yet
Jadual Berkala Chapter 6: Periodic Table Pengenalan kepada Penyiasatan Saintifik
6.1 Aim: To identify the position of metals, non-metals and inert gases in the Periodic Table. Instruction 1. Based on the Periodic Table, identify the position of metals, non-metals and inert gases. 2. State five examples of the elements in the following table. Metal
Non-metal
Inert gas
Differences between Metals and Non-metals Some elements have the same characteristics that allow these elements to be classified into two main categories, metal and non-metal. What are the differences between metals and non-metals? Metals
Similarity
Non-metals
• Both are elements Differences Shiny
Appearance
Dull
Ductile
Ductility
Brittle
Malleable
Malleability
Non-malleable
High
Tensile strength
Low (break easily)
Good
Electrical conductivity
Poor (except carbon)
Good
Heat conductivity
Poor
High
Density
Low
High
Melting point and boiling point
Low
Figure 6.8 The differences between metals and non-metals Chapter Bab 6
169
Metals
Science Exploration There are elements that cannot be classified into metals and non-metals such as germanium and silicon. These elements are semi-metals because both of them possess the characteristics of metals and non-metals.
Aluminium • Malleable • Strong and light • Grey and shiny
Hoe is made of iron
Iron • • • • •
Strong Malleable Magnetic substance A good electric conductor Grey
Copper • • • • •
Strong Rustproof Ductile (bends easily) A good electric conductor Brown
Copper wire
Zinc roof
Zinc • Strong • Grey • A good electric conductor Figure 6.9 Examples of metals and their characteristics 170
Chapter 6
Jadual Berkala Chapter 6: Periodic Table Pengenalan kepada Penyiasatan Saintifik
Non-metals Iodine • Black crystal • Poisonous • Antiseptic (prevent injuries from bacterial infection)
Iodine
Iodine
Iodine Iodine is used as an antiseptic substance
Chlorine • Greenish yellow gas • Bleaching agent • Poisonous Chlorine
Bleaching agent is made from chlorine
Chlorine
Sulphur • Yellow powder • Poisonous Sulphur can harden rubber tyres
Carbon is used to make racquets
Carbon • • • •
Black Smooth Light The only non-metal element that can conduct electricity
Pencil lead is made of carbon
Figure 6.10 Examples of non-metals and their characteristics Chapter Bab 6
171
Experiment
6.2
Problem statement: What are the differences between metals and non-metals? Aim: To study the characteristics of metals and non-metals (I) Appearance of metals and non-metals Hypothesis: Metals have a shiny surface
Copper rod
Variables Manipulated variable: Type of material
Sandpaper (a)
Responding variable: The appearance of the material
Carbon rod
Constant variable: Size of material Materials and apparatus: Copper rod, carbon rod, sandpaper.
(b)
Figure 6.11
Procedure 1. Rub the surface of a copper rod and carbon rod with sandpaper (Figure 6.11). 2. Observe the appearance of the copper rod and carbon rod surface. 3. Record your observation. (II) Ductility Hypothesis: Metals are ductile.
Copper wire
Variables Manipulated variable: Type of material Responding variable: The ductility of material
Figure 6.12
Constant variable: Size of material Materials and apparatus: Copper wire, pencil lead. Procedure 1. Bend a copper wire to form a circle (Figure 6.12). 2. Repeat step 1 with a pencil lead (Figure 6.13). 3. Record your observation.
Pencil lead
Figure 6.13
(III) Malleability Hypothesis: Metals are malleable. Variables Manipulated variable: Type of material Responding variable: The malleability of material Constant variable: Size of material
Hammer Iron piece
Materials and apparatus : Iron piece, copper piece, sulphur piece, hammer, wooden block.
172
Chapter 6
Wooden block
Figure 6.14
Jadual Berkala Chapter 6: Periodic Table Pengenalan kepada Penyiasatan Saintifik
Procedure 1. Knock an iron piece on a wooden block using a hammer several times (Figure 6.14). 2. Observe the changes in the shape of the iron piece. 3. Repeat steps 1 and 2 using the copper and sulphur piece. 4. Record your observation. (IV) Electrical conductivity Hypothesis: Metals conduct electricity. Variables Manipulated variable: Type of material
Dry cell
Ammeter A
Responding variable: The deflection of the ammeter's needle
Switch X
Crocodile clip
Constant variable: Size of material
Y Iron rod Crocodile clip
Figure 6.15
Materials and apparatus: Dry cell, ammeter, crocodile clips, iron rod, carbon rod, sulphur rod. Procedure 1. Set up the apparatus as shown in Figure 6.15. 2. Connect the ends of an iron rod with crocodile clips. 3. Observe the deflection of the ammeter's needle. 4. Repeat steps 2 and 3 by replacing the iron rod with carbon rod and sulphur rod. 5. Record your observation. (V) Heat conductivity
Carbon rod
Hypothesis: Metals conduct heat. Variables Manipulated variable: Type of material Responding variable: Time taken for the thumbtack to drop
Wax
Retort stand with clamp
Constant variable: Size of material
Thumbtack Candle
Figure 6.16
Materials and apparatus: Carbon rod, iron rod, copper rod, candle, stopwatch, thumbtack, wax, retort stand with clamp. Procedure 1. Clamp a carbon rod to the retort stand. 2. Put the thumbtack at the end of the carbon rod. 3. Heat the other end of the carbon rod (Figure 6.16). 4. Observe and record the time taken for the thumbtack to drop. 5. Repeat steps 1-4 by using an iron rod and copper rod.
Chapter Bab 6
173
(VI) Melting point Hypothesis: The melting point of metals are higher.
These activities might produce poisonous gases. Do these activities in a fume chamber.
Variables Manipulated variable: Type of materials Responding variable: Melting point of material Constant variable: Quantity of materials Materials and apparatus: Thermometer (0-360°C), crucible, Bunsen burner, pipeclay triangle, tripod stand, tin powder, sulphur powder. Procedure 1. Heat tin powder in a crucible (Figure 6.17). 2. Observe and record the melting point of the tin powder. 3. Repeat steps 1 and 2 with sulphur powder. 4. Record your observation.
Thermometer
Tin powder
Crucible Pipeclay triangle Heat
Tripod stand
Figure 6.17
Results Physical characteristic Appearance Ductility Malleability Electrical conductivity Heat conductivity Melting point
Metal
Non-metal
Conclusion: Are the hypotheses accepted? Questions 1. What is the difference between the appearance of copper rod and carbon rod surface? 2. Between copper wire and pencil lead, which one can be bent? 3. Between iron and sulphur pieces, which one is malleable? 4. Which one can conduct electricity - iron, carbon or sulphur? 5. Between iron and carbon rod, which one can conduct heat? 6. Between tin and sulphur powder, which one has a higher melting point?
174
Chapter 6
Jadual Berkala Chapter 6: Periodic Table Pengenalan kepada Penyiasatan Saintifik
Appreciate the Order of Elements that Exist in Nature There are numerous natural elements found on Earth that benefit humans. Examples of the usage of these elements are:
Antoine Lavoisier was the first scientist who classified elements as metals and non-metals.
jewellery made of gold, silver and platinum. in construction, transportation, health, medicine, agriculture and industries.
Photograph 6.2 Antoine Lavoisier
We must also appreciate the scientists who have found and arranged the elements systematically in the Periodic Table. A lot of time was spent on researching the characteristics of these elements.
6.3
21
ISS
Aim: To present the order of elements that exist in nature Instruction 1. Work in groups. 2. Do an Internet research on the reasons why scientists are still searching for a new way to present the Periodic Table. 3. Type the word “Periodic Table” on your search engine and click on “Images”. You will find various versions of the Periodic Table including the table arranged by Stowe and Tarantola. Study how the elements were arranged by them. 4. Make a creative presentation of your findings from the Internet.
6.1 1. State the subatomic particles. 2. Why is an atom neutral? 3. What is meant by element and compound? 4. Explain briefly the difference between atom and molecule. 5. How are the elements arranged in the Periodic Table? 6. Classify the elements below to metals and non-metals.
carbon, magnesium, iodine, chlorine, neon, argon, aluminium, copper, iron, gold, mercury
7. You are given element X. What should you do to identify the element?
Chapter Bab 6
175
6.2
Mixtures
Let’s learn • Communicate about examples of mixtures in daily life. • Solve problem of separating mixtures through activities based on the different characteristics of material and physical methods.
A
mixture consists of two or more elements or compounds mixed physically. Let us see some examples of mixtures (Figure 6.18). Can you list a few more examples of a mixtures that you always use?
Cocktail
Mixture of solid and liquid Some drinks like cocktail and 'air batu campur' are made from a combination of solid and liquid
̕Air batu campur ̕
Figure 6.18 Example of mixtures
Methods to Separate Mixtures How can a mixture be separated? As the mixture is formed physically, it can be separated physically too. For example, a sandwich is made of bread, vegetables and meat. Therefore, we can separate the ingredients easily through a physical method.
Photograph 6.3 Salad and sandwich are examples of mixtures that can be separated easily through a physical method. 176
Chapter 6
Jadual Berkala Chapter 6: Periodic Table Pengenalan kepada Penyiasatan Saintifik
Figure 6.19 shows a few methods to separate mixtures. Separation method
Filtration Distillation
Separation by using magnet
Floatation
Sieving Chromatography
Sedimentation
Figure 6.19 Methods to separate mixtures
Photograph 6.4 Impurities can be removed from flour by the sieving method.
Photograph 6.5 Harmful substances in food colouring can be detected by the chromatography method.
The separation method depends on:
ent in
ces pres • Physical properties of the substan the mixture
• Substance(s) to be obtained from the mixture
Science in Life
Why are you using this strainer, dad?
I want to separate the coffee powder from the coffee drink. You might choke if you drink unfiltered coffee.
Chapter Bab 6
177
(a) Filtration Filtration is a method used to separate an insoluble solid from a mixture of solid and liquid.
Filter paper separates coffee powder from a coffee drink.
Photograph 6.6 Example of filtration
Let us do Activity 6.4 to learn how to separate a mixture using filtration method.
6.4 Aim: To separate a mixture using filtration method Materials and apparatus: Sand, distilled water, filter paper, filter funnel, two 50 ml beakers, spatula, glass rod, retort stand with clamp. Instruction Glass rod
Mixture of sand and water Filter paper Residue Filter funnel
Retort stand with clamp
Filtrate
Figure 6.20
1. Add two spatulas of sand to 30 ml of water in a beaker. 2. Stir the mixture of sand and water for two minutes. 3. Filter the mixture (Figure 6.20). 4. Record your observation. Questions 1. What are the states of matter of sand and water? 2. Can the sand be separated physically from water? 3. Name the residue and filtrate in this activity. 178
Chapter 6
Jadual Berkala Chapter 6: Periodic Table Pengenalan kepada Penyiasatan Saintifik
(b) Distillation Distillation is the method used to separate a completely miscible liquid-liquid mixture that have different boiling points. How does distillation work? Do Activity 6.5 to find out how distillation is carried out. Distillation www.bbc.co.uk
6.5 Aim: To separate a mixture using distillation method. Apparatus and Materials: Mixture of water and alcohol, porcelain chips, thermometer, tripod stand, Bunsen burner, wire gauze, Liebig condenser, retort stand with clamp, round-bottom flask, beaker. Instruction Thermometer Retort stand with clamp Water out Round-bottom flask
Liebig condenser
Water + alcohol Wire gauze Water in
Porcelain chips Heat
Beaker
Figure 6.21
1. Pour the mixture of water and alcohol into the round-bottom flask until it is half full and add in some porcelain chips. 2. Flow the water through the Liebig condenser (Figure 6.21). 3. Heat the mixture of water and alcohol and collect the liquid that flows out of the Liebig condenser using a beaker. 4. Record the temperature of the liquid. Determine the boiling point of the liquid. Questions 1. At what temperature does the liquid start to flow out of the condenser? 2. What is the use of porcelain chips in this experiment?
Chapter Bab 6
179
Condenser
Boiled rose petals with water
Fragrant water collected
Figure 6.22 Perfume is produced through distillation
Photograph 6.7 Perfume
(c) Separation Using Magnet If you hold a magnet close to a box of iron nails mixed with sand, what would happen? Iron nails are metals and magnetic substance. Hence, they will be attracted to the magnet. But, sand is not a magnetic substance. Therefore, it will remain inside the box. Magnetic attraction can be used to separate two solid mixtures in which one of the substances is magnetic and the other is not. Iron, nickel and cobalt are examples of magnetic metals. Meanwhile, gold, bronze and aluminium are examples of non-magnetic metals. Science Exploration Most food industries use a magnet separator to ensure that iron particles are not mixed with the food products.
Photograph 6.8 Iron nails are attracted to a magnet
Photograph 6.9 A strong magnet is used to salvage iron and steel from a junkyard
Magnet
180
Chapter 6
Jadual Berkala Chapter 6: Periodic Table Pengenalan kepada Penyiasatan Saintifik
6.6 Aim: To separate a mixture using magnet. Materials and apparatus: Mixture of iron and sulphur powder, spatula, Petri dish, magnet bar, paper. Instruction 1. Put one spatula of iron powder and sulphur powder into a Petri dish. 2. Hold a magnet bar near the mixture (Figure 6.23).
Magnet bar Paper Petri dish Mixture of iron powder and sulphur powder
Figure 6.23
Questions 1. Which powder will be attracted to the magnet? 2. Is the powder that you answered in question 1, a metal or non-metal? (d) Sedimentation method What can you observe when sand is poured into a beaker filled with water? Look at Photograph 6.10. Two layers are formed in which the water is at the upper layer and the sand is deposited at the base of the beaker. This is because the sand is not soluble in water and has a higher density. Therefore, the sedimentation method is used to separate a liquid and insoluble solid mixture. Let us carry out the sedimentation method in Activity 6.7.
Water
+
= Sand
Water
Sand
Mixture of water and sand
Photograph 6.10 Sand deposited at the base of the beaker filled with water Chapter Bab 6
181
6.7 Aim: To separate a mixture using sedimentation method Materials and apparatus: Silty solution, two 100 ml beakers, glass rod Instruction Glass rod
Sand Glass rod
Distilled water Sand
Clear water
Figure 6.24 (a)
Figure 6.24 (b)
1. Pour 50 ml of silty solution into a 100 ml beaker. 2. Stir the silty solution by using a glass rod. (Figure 6.24 (a)). 3. Observe the water and silt after a while. 4. Slowly, pour the clear water from the beaker into an empty beaker (Figure 6.24(b)). 5. Observe the sediment left inside the beaker. Questions 1. Which substance is left inside the beaker? 2. Can water and sand be separated physically? (e) Floatation Method Floatation method can be used to separate soluble and insoluble materials in water. For example, oil has a lower density than water. Therefore, oil will float on the water surface. A separating funnel can be used to separate the oil and water. Do Activity 6.8 to understand this method further.
Photograph 6.11 Oil floats on the water surface 182
Chapter 6
Jadual Berkala Chapter 6: Periodic Table Pengenalan kepada Penyiasatan Saintifik
6.8 Aim: To separate a mixture using the floatation method. Materials and apparatus: Mixture of water and oil, beakers, separating funnel, 100 ml measuring cylinder, retort stand with clamp. Instruction Separating funnel Oil Water
Retort stand with clamp
Tap Beaker Water
Figure 6.25
1. Pour 100 ml water and oil mixture into a beaker. Record your observation. 2. Pour the mixture into a separating funnel (Figure 6.25). 3. Separate the water and oil using different beakers. Questions 1. Between water and oil, which one floats? Why? 2. Can oil and water be separated physically? (f)
Chromatography Method
Separation methods like filtration and distillation need a large amount of mixture to separate the substances. How is a small amount of mixture separated? One of the methods is by using chromatography. This method is usually used to check document fraud by separating the colours from the ink used. Besides that, the chromatography method also allows us to identify if there are any harmful food colourings present in our food.
Science Exploration There are athletes who use illegal drugs to increase their energy and stamina. Urine samples are tested to detect the drug content inside the body by using the chromatography method.
Food colourings
Photograph 6.12 Various types of food with food colourings Chapter Bab 6
183
6.9 Aim: To separate a mixture by using chromatography method. Materials and apparatus: 250 ml beaker, distilled water, filter paper, ruler, whiteboard marker pen (red, green and blue ink), skewer. Instruction Skewer Filter paper
Filter paper
Beaker
Distilled water
Figure 6.27
Figure 6.26
1. Prepare a piece of filter paper with the measurement of 5 cm × 12 cm. 2. Draw a line 1.5 cm from the edge of the paper with a pencil (Figure 6.26). 3. Draw three dots along the line using different whiteboard marker pens. Hang the filter paper in the beaker using a skewer and dip the end of the paper into the distilled water. Make sure the water does not touch the dots (Figure 6.27). 4. Observe for 30 minutes. 5. Record your observation. Questions 1. What are the colours produced on the filter paper? 2. Is the colour produced the same as the ink of the whiteboard marker pen? Chromatography method www.bbc.co.uk
6.2 1. Define mixture. 2. Match the following mixtures according to its suitable separation method. Type of mixture Paper clips and glass fragments Water and ethanol Three types of water-soluble ink Soil and water Oil and water Coffee powder and water
• • • • • •
• • • • • •
Separation method Filtration Distillation Chromatography Using magnet Sedimentation Floatation
3. If you were given a mixture that contains rice and sand, can you separate them using filtration method? Why? 184
Chapter 6
Jadual Berkala Chapter 6: Periodic Table Pengenalan kepada Penyiasatan Saintifik
6.3
Compounds
Let’s learn • • • • • •
Communicate about compounds in daily life. Demonstrate the formation of compounds between metals and non-metals. Conclude that mass is conserved during a chemical change. Separate compounds using chemical methods. Differentiate between chemical change and physical change. Differentiate between mixtures and compounds.
A
compound consists of two or more elements that are mixed chemically. This newly formed product has its own characteristics. There are a lot of compounds that we use such as salt, sugar, chalk, marble, polythene (a type of plastic) and water.
Building blocks are made of polythene, which is a combination of carbon and hydrogen
Science Exploration Rusting is an example of a compound formed by a chemical reaction between iron and oxygen.
Photograph 6.13 A rusty padlock
Water consists of hydrogen and oxygen
Tiles are made from marble which is a combination of calcium, carbon and oxygen
Photograph 6.14 Examples of compounds
6.10 Aim: To show the usage of compounds in daily life. Instruction 1. Work in groups. 2. Prepare a creative multimedia presentation on the examples of compounds that exist around you. 3. Present to your class. Chapter Bab 6
185
How do metal and non-metal elements combine chemically to form a compound? Magnesium, zinc, iron and copper react with oxygen to form the metal oxide.
magnesium aluminium zinc iron copper
+ + + + +
oxygen oxygen oxygen oxygen oxygen
magnesium oxide aluminium oxide zinc oxide iron oxide copper oxide
There are some metals that react with water to form alkali compounds and release hydrogen gas. These elements are known as alkali metals. Examples of alkali metals are lithium, sodium and potassium.
lithium sodium potassium
+ + +
water water water
lithium hydroxide + sodium hydroxide + potassium hydroxide +
hydrogen gas hydrogen gas hydrogen gas
Iron and sulphur powder will form iron sulphide when heated. iron
+
sulphur
iron sulphide
6.11 Aim: To produce a compound Materials and apparatus: Sulphur powder, iron powder, Bunsen burner, crucible with lid, tripod stand, pipeclay triangle, weighing balance Procedure Lid
Sulphur powder + iron powder
Crucible
Pipeclay triangle Heat
Figure 6.28
186
Chapter 6
Jadual Berkala Chapter 6: Periodic Table Pengenalan kepada Penyiasatan Saintifik
1. Put one spatula of sulphur powder and one spatula of iron powder into the crucible. Stir well. Record the colour of the mixture. 2. Weigh the mixture. Record the initial mass. 3. Heat the mixture until the colour changes (Figure 6.28). 4. Let the product cool. Weigh and record the final mass of the product. Questions 1. What is the colour of the mixture when it is heated? 2. Write the word equation of the chemical reaction that occurred. 3. What is the product of this reaction? 4. Is there any change in the mass of the compound before and after heating? After carrying out Activity 6.11, you can see that a metal and a non-metal form a compound when heated together and the total mass before and after heating is the same and does not change. This phenomenon always occurs in our daily life. All mineral salts that are found in nature exist in the form of compounds due to the chemical reaction that occurs, except for gold, silver and platinum.
Methods to Separate Compounds Compounds cannot be separated physically like mixtures because the elements in a compound are bonded chemically. Therefore, a compound can only be separated chemically by electrolysis. What is electrolysis?
its Electrolysis is a chemical decomposition of a compound to . elements by passing an electric current through the compound Let us see how oxygen and hydrogen are separated from water through electrolysis in Figure 6.29. Oxygen
• Water consists of hydrogen and oxygen. • Therefore, to separate the hydrogen and oxygen from water, the water must undergo the electrolysis process. • Figure 6.29 shows how electrolysis is done. This process produces hydrogen gas at the negative electrode (cathode) and oxygen gas at the positive electrode (anode).
Hydrogen
Water + sulphuric acid Cathode
Anode
A Ammeter Dry cells
Figure 6.29 Electrolysis of water
Chapter Bab 6
187
Physical Change and Chemical Change All substances undergo changes. These changes can be divided into two; physical change and chemical change. What is meant by physical change and chemical change? The differences between physical and chemical changes
Physical change does not form a new substance.
Chemical change forms a new substance that is different from the original substances.
Examples: Ice melting, water freezing, water boiling
Examples: Rusting of iron, photosynthesis, decaying of leaf and cell respiration
Figure 6.30 The differences between physical and chemical changes
Comparison between physical change and chemical change is shown in Figure 6.31
Does not form new substance
The properties of the substances remain the same
The chemical composition of the substances remain the same
Occurs to matter
Physical change
Needs less energy
Forms new substance
Chemical change
Needs energy
Needs more energy
Figure 6.31 Comparison between physical change and chemical change 188
Chapter 6
The properties of the substances and products are not the same
The substances and products have different chemical composition
Jadual Berkala Chapter 6: Periodic Table Pengenalan kepada Penyiasatan Saintifik
Differences between Mixtures and Compounds After learning about mixtures and compounds, can you differentiate both of them? Table 6.2 shows the differences between mixtures and compounds. Table 6.2 The differences between mixtures and compounds
Mixtures No No Physical Same
Characteristic Formation of new substances Chemical bond Separation method Properties of new substances compared to the original
Compounds Yes Yes Chemical Different
6.12 Aim: To prepare a multimedia presentation on the similarities and differences between mixtures and compounds Instruction 1. Work in groups. 2. Compare and contrast between mixtures and compounds. 3. You must include pictures and graphics to show your understanding of this topic. 4. Prepare a multimedia presentation of your discussion. 5. Present your discussion in class.
6.3 1. Define compound. 2. List five examples of compounds. 3. How can you separate a compound? 4. State the differences between a mixture and a compound.
Chapter Bab 6
189
190
Chapter 6
Separation method
Mixture
can be differentiated through
Non-metal
Chromatography
Floatation
Boiling point and melting point
Malleability
Ductility
Appearance
Metal
classified into
Periodic Table
Sedimentation
Neutron
Electron
Proton
Subatomic particles
Atom
consists of
arranged in
Electrical and heat conductivity
combine physically
Chemical change
Element
Separation by using magnet
Distillation
combine chemically
Changes in substance Physical change
Filtration
Electrolysis
Method of separation
Compound
Semi-metal
Jadual Berkala Chapter 6: Periodic Table Pengenalan kepada Penyiasatan Saintifik
After studying this chapter, you can: 6.1 Classification of Elements Conclude that all matter consists of atoms. Differentiate between atoms and molecules as well as elements and compounds. Identify the position of metals, non-metals and inert gases in the Periodic Table. Differentiate the characteristics of metals and non-metals. 6.2 Mixtures Communicate about examples of mixtures in daily life. Solve problems of separating mixtures. 6.3 Compounds Communicate about compounds in daily life. Demonstrate the formation of compounds from metals and non-metals. Conclude that mass is conserved during chemical change. Separate compounds through chemical methods. Differentiate between chemical change and physical change. Differentiate between mixtures and compounds.
Summative Practice
6
1. Figure 1 shows three shapes - circle, square and pentagon which represent atoms from different elements.
Based on Figure 1, identify the combination of atoms that represent (a) molecule of a compound. (b) molecule of an element that consists of two atoms. (c) molecule of an element that consists of three atoms. (b)
(a) (e) (f)
(d)
(c)
(g)
(h) (j)
(i) (l)
(m)
(k) (n)
(p) (o)
Figure 1 Chapter Bab 6
191
2. Figure 2 shows part of the Periodic Table.
P R
Figure 2
(a) (b) (c)
State the type of element for P and R. What are the differences in physical characteristics of P and R? Iron is a type of metal that has a shiny surface. However, iron can rust easily. Explain.
(d) Graphite is an example of carbon. What are the characteristics of graphite that make it suitable to be used as pencil lead? 3. Noraini wants to make pineapple jam using the recipe given by her mother as shown in Figure 3. Pineapple Jam 1. Remove pineapple skin and grate the pineapple. 2. Blend the pineapple using a blender. 3. Remove the excess juice. 4. Cook the blended pineapple on medium heat. Add some sugar, salt and yellow food colouring. 5. Stir the mixture until it thickens and is sticky. 6. Then, cool the jam and keep it in the refrigerator. Figure 3
(a) Name the separation method used in the recipe. (b) Which step involves the separation method that you stated in 3(a)? 4. Kumutha is given a mixture of sand, iron filings, sawdust and salt. She separates the mixture by following the four steps in Figure 4. The letters A, B, C and D represent the substances in the mixture.
192
Chapter 6
Jadual Berkala Chapter 6: Periodic Table Pengenalan kepada Penyiasatan Saintifik
A, B, C, D Step 1: Magnetic attraction
A
B, C, D B, C, D
Step 2: Dissolve in water and remove substance that float
C + D + water
B
C + D + water Step 3: Filtration
D + water
C
D + water Step 4: Evaporation of water
water
D
Figure 4
(a) Identify substance A, B, C and D whether they are sand, iron filings, sawdust or salt. (b) Differentiate the density of B and C. Why can B be separated from the mixture in Step 2? Explain. (c) If D is replaced with sugar, can it still be separated from the water by applying Step 4? (d) Is there another way that Kumutha could do to separate the mixture in Step 4? Explain your answer.
Beaker
5. A few students set up the apparatus as shown in Figure 5 to separate sand and salt. They found out that the mixture took a longer time to be filtered. Therefore, they decided to stir the mixture on the filter paper using a glass rod. Is it a good idea? Give your reason (s).
Glass rod Retort stand with clamp Filter paper
Mixture of sand and salt solution Filter funnel Sand
Salt solution
Figure 5
6. Athirah accidentaly spills sand into a salt container. How can she separate the salt and sand from the mixture? State the separation method that she needs to use. Explain the steps in the separation method.
Chapter Bab 6
193
Chapter
7
Air
Why must we take care of the air around us? What is the composition of the air? How can we maintain the quality of the air?
Let’s Study: Composition of Air Combustion Air Pollution 194
Bab Chapter Chapter 7 76
Udara 7: Air Chapter Pengenalan kepada Penyiasatan Saintifik
IN SCIENCE BULALLAYESITA
AIR POLLUTANT
INDEX (API) IN M
cades, or the last several de er countries oth Malaysia and a few riencing pe ex in East Asia have been in nearby ing rn bu haze caused by open ts the ec aff ze ha countries. Prolonged those lly cia pe es health of the people, le are op Pe s. lem with respiratory prob tant llu Po r Ai advised to monitor the as are ve cti pe Index (API) at their res by en giv e vic ad in accordance to the Air is t ha W y. rit the local health autho Pollutant Index?
F
a guide for us to This index is used as quality and its impact know the level of air ble 1 shows the towards our health. Ta llutant Index. Po classification of Air t Index (API) level
Table 1 Air Pollutan API 0-50
Level of Pollution Good Moderate
51-100
101-200
201-300 >300
Unhealthy
Very Unhealthy Hazardous
Oxygen Carbon dioxide Nitrogen Inert gases Helium Neon Argon Krypton
Xenon Carbon cycle Oxygen cycle Global warming Greenhouse effect Combustion Fire extinguisher Air pollution
Chapter 77 Chapter
195
7.1
Composition of Air
Let’s learn • • • • •
Plan ways to determine and record the composition of air. Synthesise the composition of air from a pie chart. Justify the importance of oxygen, nitrogen, carbon dioxide and inert gases in daily life. Appreciate the carbon cycle and the oxygen cycle in maintaining the composition of gases in the air. Solve problems when there is/are interferences to the oxygen and the carbon cycle.
Y
ou have learned that air has mass and occupies space in Chapter 5. All living things need air to survive. Clean air does not have colour or smell. Therefore, we cannot see the air even though it has a lot of substances in it. (Photograph 7.1). What are the contents of air? Air is a mixture of several gases which are nitrogen (78%), oxygen (21%), carbon dioxide (0.03%) and inert gases (0.97%) such as helium, argon, neon, xenon and krypton. Other components that exist in the air are microorganisms, water vapour and dust. The quantity of these components is low and varies according to place and time. For example, there is more water vapour in forests or after the rain than during a hot day.
Photograph 7.1 Air cannot be seen
B
Nitrogen 78% Carbon dioxide 0.03%
Oxygen 21%
Inert gases and other substances 0.97%
What is the relationship between the water vapour content in the air and formation of cloud and rain?
Science Exploration Some sicknesses such as fever are caused by microorganisms in the air.
Figure 7.1 Composition of air represented in a pie chart
196
Chapter 7
Udara 7: Air Chapter Pengenalan kepada Penyiasatan Saintifik
Carry out Activity 7.1 to determine the percentage of oxygen in the air.
7.1 Aim: To determine the percentage of oxygen in the air Materials and apparatus: Candle, plasticine, matches, glass basin, permanent marker pen, gas jar, gas jar stand, water. Instruction
Gas jar Candle Glass basin Water Plasticine
Water level indicator Gas jar stand
(a)
The gas jar is divided into five equal parts and marked with marker pen
Gas jar
Water level indicator
(b)
Figure 7.2 Set-up of apparatus before the candle is lit
1. Prepare the apparatus as shown in Figure 7.2 (a). 2. Divide the gas jar into five equal parts (Figure 7.2 (b)). Candle 3. Light the candle and invert the gas jar over the candle (Figure 7.3). 4. Observe and record the changes in the water level when the flame extinguishes. 5. Make a conclusion on the percentage of oxygen Figure 7.3 Set-up of apparatus after in the air.
the candle is lit
Questions 1. What happened to the flame of the candle after a period of time? Why? 2. What happened to the water level at the end of this activity? Give reason(s) to the changes. 3. What is the percentage of oxygen in the air based on this activity? At the end of Activity 7.1, the water rose to one fifth of the gas jar. This shows that one fifth of the air contains oxygen. Therefore, the air consists of 20% oxygen.
Chapter 7
197
Is Air a Mixture? Is air a compound or a mixture?
Air is a mixture.
Figure 7.4 Air is a mixture
Do you still remember the differences between mixtures and compounds which you have learned in Chapter 6? Why is air classified as a mixture and not a compound? Air is a mixture because the components can be separated by a physical method, which is fractional distillation. Science Exploration
The Importance of Gases Have you ever imagined life without air? What is the importance of oxygen, carbon dioxide, nitrogen and inert gases?
Photograph 7.2 One of the importance of oxygen is for combustion
198
Chapter 7
Fractional distillation is separation of a liquid mixture into fractions with different boiling points through boiling and condensation.
Udara 7: Air Chapter Pengenalan kepada Penyiasatan Saintifik
Importance of gases
Oxygen
Carbon dioxide
Nitrogen
Inert gas
Light bulb
Rocket
• Respiration • Combustion of rocket engine at high altitudes • Welding and steel cutting • Preparation of various compounds
Fire extinguisher
• Photosynthesis • Production of carbonated drinks • Fire extinguisher • Carbon cycle
Nitrogen fertiliser
• Production of nitric acid and ammonia • Nitrogen cycle • Liquid nitrogen as cooling agent
• Helium is used to fill hot air balloons and weather balloons • Neon gas is used in advertising lights • Argon gas is used in light bulbs
Oxygen Helium Carbon dioxide
Figure 7.5 Importance of gases Chapter 7
199
Carbon cycle Carbon dioxide in atmosphere burning of fossil fuels
decomposition photosynthesis
respiration respiration
is eaten Animal
Green plants dead organisms
Release carbon dioxide Use carbon dioxide
form
fossil fuels (petroleum, natural gas and coal)
Figure 7.6 The carbon cycle
How does the carbon cycle maintain the content of carbon dioxide in the air?
Carbon cycle is the cycle that maintains the content of carbon dioxide in the air by continuously taking carbon dioxide from the air and returning it to the air.
200
Chapter 7
• Carbon cycle begins when green plants absorb carbon dioxide through photosynthesis. • Animals that eat the plants obtain carbon elements from them. • When the plants and animals die, they decompose. • Decomposition caused by bacteria and fungi in the soil releases carbon dioxide. • Burning of fossil fuels that contain carbon like coal and petrol also releases carbon dioxide. • During respiration, all plants and animals release carbon dioxide. • These processes such as decomposition, combustion and respiration are balanced by photosynthesis.
Udara 7: Air Chapter Pengenalan kepada Penyiasatan Saintifik
Oxygen Cycle Oxygen in atmosphere Photosynthesis
Respiration
Respiration Combustion
Rusting Animals
Green plants
Decomposition of waste materials and dead organisms
Decomposition of waste materials and dead organisms Carbon dioxide in atmosphere Use oxygen Release oxygen
Figure 7.7 The oxygen cycle Video on oxygen cycle
How does the oxygen cycle maintain the content of oxygen in the air?
Oxygen cycle is a continuous cycle that takes oxygen from the air and returns it to the air.
• Oxygen needed in respiration, rusting, combustion and decomposition is obtained from photosynthesis.
We must always appreciate the carbon and oxygen cycles that maintain the gas content in the air. All activities that harm the air must be reduced.
Chapter 7
201
7.2 Aim: To gather information regarding the importance of gases, the oxygen cycle and carbon cycle Instruction 1. Work in groups. 2. Find information on the importance of the following gases: (a) oxygen (b) carbon dioxide (c) nitrogen (d) inert gases 3. Record the information gathered using a suitable thinking map. 4. Find the information on oxygen and carbon cycles and how they maintain the percentage of gases in the atmosphere. 5. Present it in class.
Ways to Prevent Interferences in the Oxygen and Carbon Cycles Our environment is being destroyed by human activities such as logging and the uncontrolled usage of pesticides in agriculture. This will increase the amount of carbon dioxide which interferes with natural cycles including the oxygen and carbon cycles. Global warming and the greenhouse effect are among the consequences of this interference.
Photograph 7.3 Fertile lands can become dry because of global warming 202
Chapter 7
Udara 7: Air Chapter Pengenalan kepada Penyiasatan Saintifik
Photograph 7.4 shows some ways to reduce the problem of interferences to the oxygen and carbon cycles on Earth. pes tici de s
ng gi
Pro hib it i lle ga l
lo g
Avoid using exce ssiv e
Reforestation
n ur tb no Do st re fo s
se Prevent excessive relea
m fro ke o m of s
es icl h ve
Photograph 7.4 Ways to reduce problems of interferences to the oxygen and carbon cycle
7.1 1. List the composition of air. 2. How can you identify oxygen and carbon dioxide? 3. What is the importance of carbon dioxide to plants? 4. What are the effects of the increase of carbon dioxide in the air to humans? 5. As a student who appreciates the importance of the carbon and oxygen cycles, suggest ways to ensure a balance of carbon dioxide and oxygen content in the air. Chapter 7
203
7.2
Combustion
Let’s learn • • •
Conclude about the conditions needed for combustion. Relate the conditions of combustion with the principles used in the manufacture of fire extinguishers. Practise safety measures to prevent the occurrence of fire which can lead to the destruction of life and property.
Ox
el
yg
Fu
en
C
ombustion is the reaction that occurs when a substance is heated in the presence of oxygen which produces heat energy and light energy.
Heat
Figure 7.8 Three conditions needed for combustion
We can prevent combustion if we remove one of the conditions needed for combustion.
B
Why do we use water to extinguish fire?
Photograph 7.5 The candle flame is extinguished when oxygen is removed by blowing it
Photograph 7.6 How can firefighters put out this fire? 204
Chapter 7
Udara 7: Air Chapter Pengenalan kepada Penyiasatan Saintifik
Carry out Activity 7.3 to prove that fuel, oxygen and heat are needed for combustion.
7.3 Aim: To prove that fuel, oxygen and heat are needed for combustion I Fuel is needed for combustion Materials and apparatus: Bunsen burner, tongs, lighter, glass rod, wood, candle, stone Instruction 1. Light a Bunsen burner. 2. Hold a glass rod over the fire by using tongs. 3. Observe whether or not the glass rod burns. 4. Record your observation in a table. 5. Repeat steps 2 to 4 by using wood, candle and stone. Material (a) Glass rod (b) Wood (c) Candle (d) Stone
Observation
Questions 1. Based on your observation, classify the materials into fuel and non-fuel. 2. What is the conclusion that you can make from this activity? II Oxygen is needed for combustion Materials and apparatus: Gas jar, two white tiles, two candles of the same size, plasticine, lighter Instruction 1. Hold two candles of the same size on white tiles by using plasticine (Figure 7.9). 2. Light candles X and Y. 3. Turn a gas jar over candle X. 4. Observe which candle extinguishes first.
Gas jar
Plasticine
White
Questions tile Candle Y Candle X 1. Which candle burns longer? Why? Figure 7.9 2. What is the gas used during the burning of candle? 3. What is the conclusion that you can make from this activity?
White tile
Chapter 7
205
III Heat is needed for combustion Materials and apparatus: Match stick, match stick which has been stored inside the refrigerator, matchbox Instruction 1. Label the match stick which has been stored inside the refrigerator as P and the other match stick as Q. 2. Light match sticks P and Q. Observe the changes that occur. Question: 1. Do both match sticks ignite? Why? 2. What is the conclusion that you can make from this activity?
Fire Extinguisher Have you gone through a fire drill at your school? The firefighters would have shown the correct way to use the fire extinguisher. The fire extinguisher is a protective tool that is used to put out a fire or handle a small fire, usually during an emergency. The substance used in a fire extinguisher differs based on the type of materials on fire as shown in Table 7.1. Figure 7.10 A fire extinguisher Table 7.1 Types of fire extinguisher for different sources of fire
Material on fire Solid Liquid Gas Metal
Example of material Wood, cloth, paper Oil, varnish, paint Propane, acetylene, methane Potassium, sodium, magnesium, calcium
Science in Life Kamal, hurry up! Pour a pail of water before the fire spreads!
206
Chapter 7
Type of fire extinguisher Water, dry powder Foam, dry powder, carbon dioxide Foam, dry powder, carbon dioxide Dry powder, dry sand
No! Water is denser than oil and it will sink below the oil. The fire will not be extinguished. We must use foam!
Udara 7: Air Chapter Pengenalan kepada Penyiasatan Saintifik
As you have learned in subtopic 7.1, combustion needs oxygen, heat and fuel. Therefore, fire can be extinguished by removing one of the conditions needed for combustion using the following techniques. Science Exploration (a) Covering: cutting off the contact of the fuel with oxygen or air. For example, covering the surface of fuel Fire blanket is a special with fire blanket, wet sack, mud, sand, soil or foam. blanket made of fire resistant substances. This (b) Cooling: cooling the surface of burning materials by blanket covers the fire spraying water or a layer of carbon dioxide. and prevents oxygen from (c) Reducing the amount of burning materials/cutting seeping below the blanket off the source of fuel: this technique can be used which will eventually by separating the burning materials, keeping away extinguish the fire. materials that have not burnt yet and cutting off the supply of gas or oil.
Photograph 7.7 A fire blanket
Safety Measures to Prevent the Occurrence of Fire Keep away flammable substances from fire
Keep matches and lighters in a safe place
Do not throw away cigarette butts when they are still burning
Safety measures to prevent the occurrence of fire
Install fire alarm and smoke detector at home
Always be aware of your electrical appliances
Do not plug in too many electrical appliances to a single electrical source
Figure 7.11 Safety measures to prevent the occurrence of fire Chapter 7
207
7.2 1. Define combustion. 2. What are the conditions needed for combustion? 3. Luqman uses a fire blanket to put out a small fire at his house. How does the fire blanket work? 4. Give four ways to prevent fire. 5. Metals like potassium and sodium are kept in paraffin oil. Why?
7.4
21
ISS
Aim: To make a poster on causes of fire and ways to prevent it Instruction 1. Prepare a poster entitled ‘Causes of Fire and Ways to Prevent it’ in a group. 2. Present the best three posters on the science board of your class.
7.3
Air Pollution
Let’s learn • • • •
Define air pollution and air pollutants. Communicate about air pollutants and the causes. Justify steps to prevent and control air pollution. Solve problems on the adverse effects of air pollution.
A
ir pollution is a situation which involves the presence of any pollutants in the air. This brings harm and discomfort to living things and destroys the environment. Air pollutants come from various sources. The sources of air pollutants are shown in Figure 7.12.
Photograph 7.8 Air pollution from a factory
208
Chapter 7
Udara 7: Air Chapter Pengenalan kepada Penyiasatan Saintifik
Pollutants Smoke, soot, dust, carbon monoxide, sulphur dioxide, nitrogen dioxide, plumbum
Pollutants Radioactive materials
Sources • Exhaust of vehicles • Factories
Sources • Open burning • Cigarettes • Forest fires Sources • Construction sites • Asbestos factories • Limestone quarries
Pollutants Dust, soot, smoke
Sources Nuclear power plants
Sources Agriculture and plantation activities
Sources • Air-conditioners • Refrigerators • Aerosol sprays • Electronic factories
Pollutants Aerosol spray, chemical fertilisers
Pollutants • Dust, soot
Pollutants Chlorofluorocarbon (CFC)
Figure 7.12 Sources of air pollutants
7.5 Aim: To discuss air pollution problems in Malaysia Instruction Photograph 7.9 shows the hazy condition in Kuala Lumpur in 2015. Discuss in groups the definition of air pollution and sources of air pollutants which cause haze. Then, present your discussion in class. Photograph 7.9 Haze in Kuala Lumpur
Polluted air can cause illness and discomfort to humans. There are various steps that can be taken to prevent and control air pollution. Figures 7.13(a) and (b) show the effects of air pollution and ways to prevent and control it. Chapter 7
209
Health • Smoke and dust can cause breathing problems • Sulphur dioxide can cause respiratory problems • Carbon monoxide can cause headache, mental retardation and death • Asbestos particles can cause lung cancer • Lead particles can cause intellectual disability among children and babies
Buildings and infrastructures • Dust and soot stain buildings • Acid rain corrodes concrete and limestone buildings • Acid rain speeds up iron rusting
Causes and effects of air pollution Plants and animals • Acid rain makes the soil acidic and less fertile • Acid rain makes the source of water acidic and not suitable for aquatic life • Smoke and haze decrease the amount of sunlight reaching the Earth and decrease the rate of photosynthesis.
• • • •
Climate Smoke from factories, vehicles and open burning lead to haze Excessive carbon dioxide contributes to greenhouse effect Excessive chlorofluorocarbons (CFC) causes the thinning of the ozone layer Sulphur dioxide and nitrogen dioxide cause acid rain Figure 7.13 (a) Causes and effects of air pollution 210
Chapter 7
Udara 7: Air Chapter Pengenalan kepada Penyiasatan Saintifik
Law Enforcement • Fine smokers who smoke at restricted areas • Fine individuals who conduct open burning • Fine drivers whose vehicles emit excessive smoke • Prohibit factories from being built at housing areas
Ways to prevent and control air pollution
Education • Educate students about the effects of air pollution and ways to prevent it • Organise anti-smoking campaigns • Encourage the public to walk or ride bicycles • Encourage the usage of public transport or car pooling
Science and Technology • Implement hybrid technology in vehicles • Choose refrigerators which use hydrochlorofluorocarbons (HCFC) instead of chlorofluorocarbons (CFC) • Install filters in smoke chimneys at factories • Use catalytic converters on vehicles • Replace the use of pesticide with biological control to control pest
Figure 7.13 (b) Ways to prevent and control air pollution Chapter 7
211
7.6 Aim: To gather information on effects of air pollution on living things and the environment, and the steps taken by authorities in controlling air pollution. Instruction 1. Work in groups. 2. Each group has to choose an area in Malaysia which has a high rate of air pollution. 3. Gather the information below from your chosen area: (a) the effects of air pollution towards the health of the community, animals, plants, buildings and infrastructures. (b) efforts taken by the authority, for instance Jabatan Alam Sekitar, to overcome the air pollution problem. 4. Present your findings in class.
7.3 1. What are the pollutants that can cause haze? 2. As a student, how can you increase the awareness of air pollution in the community? 3. Give three reasons why it is important to keep the air clean. 4. Littering can also cause air pollution. Explain how littering causes air pollution. 5. Match each pollutant to its effect. Pollutant Carbon dioxide Nitrogen dioxide Chlorofluorocarbons
Effect Acid rain Greenhouse effect Thinning of the ozone layer
6. Tick (✓) the correct statement on how to control and reduce air pollution.
(a) Use materials free of chlorofluorocarbons (CFC).
(b) Use public transport.
(c) Conduct open burning.
(d) Practise reusing and recycling items.
(e) Use petrol and diesel that contain lead.
212
Chapter 7
Inert gases
Carbon dioxide
Oxygen
Nitrogen
Gas
Microorganisms
Dust
Water vapour
Other components
Composition of air
Oxygen cycle maintains the content of oxygen in the air
Carbon cycle maintains the content of carbon dioxide in the air
Carbon cycle and oxygen cycle
Air
Fuel
Heat
Oxygen
Conditions of combustion
Dry sand
Carbon dioxide
Dry powder
Water
Foam
Fire extinguisher
Combustion
Ways to prevent and control air pollution
Effects of air pollution
Air pollutants and causes
Definition
Air pollution
Udara 7: Air Chapter Pengenalan kepada Penyiasatan Saintifik
Chapter 7
213
After learning this chapter, you are able to: 7.1 Composition of Air Plan ways to determine and record the composition of air Synthesise the composition of air from a pie chart Justify the importance of oxygen, nitrogen, carbon dioxide and inert gases in daily life Appreciate the carbon cycle and the oxygen cycle in maintaining the composition of gases in the air Solve problems when there is/are interference to the oxygen and carbon cycles 7.2 Combustion Conclude about the conditions needed for combustion Relate the conditions of combustion with the principles used in the manufacture of fire extinguishers Practice safety measures to prevent the occurrence of fire which can lead to the destruction of life and property 7.3 Air Pollution Define air pollution and air pollutants Communicate about air pollutants and the causes Justify steps to prevent and control air pollution Solve problems on the adverse effects of air pollution
Summative Practice
7
1. The pie chart in Figure 1 shows the percentage of gas P, Q, R and S in the atmosphere.
Q = 21% R = 0.97% S = 0.03%
P = 78%
Figure 1 214
Chapter 7
Udara 7: Air Chapter Pengenalan kepada Penyiasatan Saintifik
(a) (b) (c) (d)
Determine gas (i) P (iii) R (ii) Q (iv) S State the importance of gas P. What would happen to the temperature of Earth if the percentage of gas S increases? Give a reason for your answer. Give one reason why air is considered a mixture.
2. Solve the crossword puzzle below with the correct answer. (c)
T
(d)
(a)
B
O
D (b)
G
N
N
E
Horizontal: (a) Carbon cycle maintains this gas in the air. (b) This gas is used to fill up light bulbs. Vertical: (c) A layer that surrounds the Earth. (d) This gas is needed in combustion.
Chapter 7
215
3. Figure 2 shows the percentage of carbon dioxide in a period of time. Carbon dioxide in atmosphere (%) 0.036 0.035 0.034 0.033 0.032 0.031 0.030 0.029 0.028 0.027 1875
1880
1885
1990
1995
2000
2005
Year
Figure 2
(a) Logging activities increase the amount of carbon dioxide in the atmosphere. How does it contribute to the increase of carbon dioxide level in the atmosphere? Explain. (b) Other than logging, give one activity that contributes to the increase of carbon dioxide in the atmosphere. (c) State two effects if the rate of carbon dioxide in the atmosphere increases continuously.
4. Ammar witnessed a fire at a workshop on his way home from school. The fire was caused by a short circuit. (a) What is combustion? (b) State the conditions of combustion. (c) Based on the situation, (i) how does one prevent such a fire from happening? (ii) what fire extinguisher is suitable?
(d) State three precautions that should be practised to prevent fire from happening.
216
Chapter 7
Udara 7: Air Chapter Pengenalan kepada Penyiasatan Saintifik
5. Figure 3 shows a situation that occurs in Kuala Lumpur.
Figure 3
(a) What is the environmental problem shown in Figure 3? (b) State two effects of the problem you mentioned in 5(a) towards health. (c) The road accident rate increases when this environmental problem occurs. Why? 6. The oxygen level in a cave would eventually decrease as we walk further into the cave.
Figure 4
(a) List a few reasons why the oxygen level decreases in the cave. (b) If we want to go into a deep cave, we are encouraged to bring torches with us in addition to torchlights as an indicator to show the presence of oxygen. How does the torch function? Explain. (c) Do you think it is good to bring torches into the cave? (d) Suggest one way to detect the oxygen level in a safer way. Give one reason for your suggestion.
Chapter 7
217
7. A company wants to do a limestone quarry project near Kampung Permai. The village headman has conducted a meeting with the villagers. The result from the meeting is as follows: Table 1
Percentage of villagers supporting the quarry project (%)
20
Percentage of villagers opposing the quarry project (%)
80
(a) Why do you think a majority of the Kampung Permai villagers oppose the quarry project? Give a cause for their concern. (b) Villagers who support the quarry project have a common reason, which gives them one advantage. What is the advantage? (c) The village headman has decided to go against the quarry project.
Is it a rational decision?
8. Assume that you are a scientist. The amount of sunlight received in East Asia has decreased due to dust produced from natural disasters such as volcano eruptions and development activities. Consequently, many plants planted by farmers die. How does this happen? Suggest ways how the farmers can solve this problem.
218
Chapter 7
Cahaya dan Chapter 8: Light Optik andPenyiasatan Optics Pengenalan kepada Saintifik
4
Energy and e Sustainability of Lif
Light is a form of energy that helps us see scenery and objects around us. Without light, the world will be dark and our life will become dull. We should be grateful for the presence of light in our life.
Chapter Bab 8
219
Chapter
8
Light and Optics
Why do the sky and the sea look blue when the sun is shining? Why does the seabed look shallow? How is the shadow of a coconut tree formed? What causes these phenomena to occur?
Let’s study: The Use of Mirrors Characteristics of Light Reflection of Light Refraction of Light
220
Bab 8 8 Chapter
Dispersion of Light Scattering of Light Addition and Subtraction of Light
Cahaya dan Chapter 8: Light Optik andPenyiasatan Optics Pengenalan kepada Saintifik
ULLETIN SCIENCE B ATION INBOW FORM
PHENOMENON OF RA
and colours began ur understanding of light nts conducted with a series of experime r 1672. He was yea by Sir Isaac Newton in the understand the to ed the first person who manag rainbow. Newton of n tio phenomenon of the forma white light into its used a prism to separate component colours.
O
Angle of reflection Real Virtual Reflection
Refraction Dispersion Object distance Image distance
Chapter Bab 8
221
8.1
The Use of Mirrors
Let’s learn • Differentiate between a real image and a virtual image. • Communicate about the characteristics of image formed by a plane mirror, concave mirror and convex mirror. • State that the object distance is equal to the image distance in a plane mirror. • Use the plane mirror to apply the concept of reflection of light. • Justify the application of concave mirrors and convex mirrors in daily life. • Construct an optical instrument to appreciate the use of these optical instruments to enhance the ability of the human senses. • Solve problems in daily life involving the application of plane mirrors, concave mirrors and convex mirrors.
We see our image in the mirror every day. Do you know what type of mirror we use? This type of mirror is a plane mirror. What image is formed in the plane mirror? Real image or virtual image? Photograph 8.1 An image seen in a mirror
8.1
Aim: To study the difference between real image and virtual image Materials and apparatus: A piece of black A4 cardboard, a piece of white A4 cardboard, a candle, pin, mirror. Instruction 1. Use a pin to pierce a hole in a black A4 cardboard. 2. Arrange the materials and apparatus as in Figure 8.1. Use a white A4 cardboard as a screen where the image will be formed. 3. Observe the image formed on the second cardboard which is used as a screen. 4. Choose a student to stand in front of a mirror as shown in Figure 8.2. Observe the image formed.
Image of candle White cardboard Pinhole as screen
Black cardboard Candle
Figure 8.1 Mirror Image
Figure 8.2 Questions 1. Is the image formed in Figure 8.1 real or virtual? 2. Compare the characteristics of the image formed in Figure 8.1 with Figure 8.2.
A real image is an image that forms on a screen, while a virtual image is an image that cannot be formed on a screen. Our image forms behind the mirror, not on the mirror screen. Therefore, the image formed by a plane mirror is a virtual image. 222
Bab 8 8 Chapter
Cahaya dan Chapter 8: Light Optik andPenyiasatan Optics Pengenalan kepada Saintifik
What are the characteristics of the image formed by a plane mirror, a concave mirror and a convex mirror (Figure 8.3)?
PlanePmirror Concave mirror ConvexRmirror P P Q Q Q R R
Figure 8.3 Types of mirrors
8.2 Aim: To determine the characteristics of the image formed by a plane mirror, concave mirror and convex mirror Materials and apparatus: Plane mirror, concave mirror, convex mirror, candle, graph paper. Instruction 1. Place a candle on a piece of graph paper in front Plane of a plane mirror as shown in Figure 8.4. mirror 2. Observe the image formed. Is the image the same size, smaller or bigger than the object? Candle 3. Repeat steps 1 and 2 by replacing the plane mirror with a concave mirror and a convex mirror. 4. Record the results in a table. Type of mirror Plane mirror Concave mirror Convex mirror
Location of image Graph paper
Figure 8.4
Image formed (same size / smaller / bigger) than object
5. Then, measure the distance of the image from the plane mirror. Distance of image from the plane mirror = squares on graph paper. Questions 1. Compare the size of the image formed in the mirrors with the size of the object. 2. Compare the distance of the image formed in the plane mirror with the distance of the object. ys
ra ht
Lig
A plane mirror applies the concept of light reflection as in Figure 8.5. Light rays that shine on the mirror will be reflected. Surface of mirror
Figure 8.5 Reflection of light
Chapter Bab 8
223
Usage of Plane Mirror, Concave Mirror and Convex Mirror Do you know that the plane mirror, concave mirror and convex mirror are widely used?
A plane mirror helps a dancer to correct his movement.
Plane mirror
A plane mirror makes a living room look spacious.
Photograph 8.2(a) Usage of plane mirrors
A concave mirror helps to magnify the image to make it easier for someone to apply make up.
Concave mirror
A concave mirror is used by a dentist to see the patient's teeth so that the image formed looks bigger and closer.
Photograph 8.2(b) Usage of concave mirrors 224
Bab 8 8 Chapter
Cahaya dan Chapter 8: Light Optik andPenyiasatan Optics Pengenalan kepada Saintifik
A convex mirror is used as a safety feature at dangerous corner of a road.
Convex mirror
Convex mirrors at the supermarket can help a shopkeeper to see every corner of the supermarket to prevent theft.
Photograph 8.2(c) Usage of convex mirrors Convex mirrors and concave mirrors http://www.animations. physics.unsw.edu.au/jw/light/ mirrors-and-images.htm
8.3
21
ICS
Aim: To discuss the usage of plane mirrors, concave mirrors and convex mirrors Instruction 1. Work in groups. 2. Discuss the usage of plane mirrors, concave mirrors and convex mirrors. 3. Present your discussion using multimedia presentation.
Chapter Bab 8
225
Optical Instruments that Apply the Concept of Reflection of Light
Periscope
Optical instruments are invented by scientists based on the concept of light reflection to enhance the ability of human senses. We should be grateful for these inventions and appreciate them. Submarine
Periscope
45°
Periscope is an instrument used in submarines to observe the sea surface. Periscope works by using the concept of reflection of light. Light from the sea surface is hit through the top mirror and is reflected. The light is then reflected again at the second mirror, right into the eye of the observer in the submarine. Let us create a simple periscope in Activity 8.4.
Mirror
45°
Mirror
Figure 8.6 A periscope
8.4 Box
Aim: To create a simple periscope
15 cm
Materials and apparatus: Two plane mirrors, box, knife. 30 cm Instruction 1
2
Two pieces of plane mirror
10 cm
Cut with a knife
15 cm
Mirrors facing each other
Cut the side of the upper and lower box to fit the width of the mirror.
Place the mirrors facing each other.
3
4
Hole 1
Object
Mirror
Hole 2 Make two holes exactly opposite each mirror.
Bab 8 8 Chapter
Be careful when using knives to prevent injuries.
See the objects through the Hole 2.
Place the object to be viewed in front of Hole 1.
Figure 8.7 Steps to create a periscope
226
14 cm
Cahaya dan Chapter 8: Light Optik andPenyiasatan Optics Pengenalan kepada Saintifik
Kaleidoscope Kaleidoscope is a toy made using plane mirrors. With this toy, you can create various amazing patterns. These patterns are obtained due to the repeated reflection of the image of the objects inside the kaleidoscope. Therefore, the number of images seen is more than the number of objects. Let's carry out Activity 8.5 to build a kaleidoscope.
8.5
Mirror card
Aim: To build a kaleidoscope Materials and apparatus: One kitchen towel roll, three pieces of mirror cards, colourful beads, two pieces of plastic discs, scissors, glue, cellophane tape, colourful paper for decoration, round black cardboard.
2 pieces of plastic discs A Scissors
Glue
Colourful beads
B
Cellophane
Instruction tape 1. Prepare the materials and Round black Kitchen apparatus as shown in Figure 8.8. cardboard towel roll 2. Prepare three pieces of mirror cards. Each one is Figure 8.8 4.3 cm in width and 21 cm in length. 3. Stick the three pieces of the mirror cards with cellophane tape to make a triangle prism. Make sure the shiny surface is facing inward. 4. Push the triangle prism into the empty roll (Figure 8.9(a)). 5. Cut two pieces of round plastic discs with a diameter of 5.3 cm respectively. 6. Attach the first plastic disc on one end of the roll, A (Figure 8.9(b)). Push the first plastic disc into the roll until it touches the triangle prism. Triangle prism
A
A
Plastic disc
Empty kitchen towel roll
B
(a)
(b)
B
Figure 8.9
7. Add colourful beads on the surface of the first plastic disc (Figure 8.10(a)). Attach the second plastic disc to cover the colourful beads (Figure 8.10(b)).
(a)
A
Plastic disc
A
(b)
B
B
Figure 8.10 Chapter Bab 8
227
8. At the other end of the kitchen towel roll, B, attach a round black cardboard which has a diameter of 5.3 cm and make a hole on it (Figure 8.11). 9. Decorate the kitchen towel roll with colourful papers according to your creativity. 10. Look at the pattern of the colourful beads formed through the hole.
Round black cardboard B
A
Figure 8.11
Science in Life
21
CPS
Situation 1 How do I see the scenery behind this wall?
Situation 2 It is dangerous to walk on this path because we cannot see anything around the corner.
Situation 3
Well, a periscope can help me.
We can fix convex mirrors at dangerous corners.
Convex mirror
You can fix a convex mirror on the bike to see things behind you.
It is good if I can see things behind me to avoid accidents. Convex mirror
228
Bab 8 8 Chapter
Cahaya dan Chapter 8: Light Optik andPenyiasatan Optics Pengenalan kepada Saintifik
8.1 1. The picture shows a man standing in front of a mirror. What type of mirror is it? State the characteristic of the image formed. 2. What is the function of plane mirrors in a periscope? 3. Why do we need plane mirrors in a lift?
8.2
Properties of Light
Let’s learn • Communicate about the properties of light.
W
hat are the properties of light? Why do we see lightning before we hear thunder?
The speed of light is 3.0 × 108 m s–1. Light travels much faster than sound, so we see the lightning before we hear the thunder.
Photograph 8.3 A lightning
Albert Einstein
Light travels in straight lines. We can see the movement of light in a light show (Photograph 8.4). Have you ever wondered how shadows are formed? Photograph 8.4 A light show
1. Sunlight travels in straight lines.
2. Umbrella is an opaque object, therefore the sunlight cannot pass through it. 3. When light is blocked by an opaque object, a shadow is formed behind the opaque object.
Photograph 8.5 Formation of shadows Chapter Bab 8
229
Do you know that your shadow will become short in the afternoon and long in the evening? Another property of light is that it can be dispersed by water droplets in the sky to form a rainbow as in Photograph 8.6. Photograph 8.7 The Sundial The Sundial was used in ancient times to determine the time during the day. The sundial used the concept that shadows are formed when the sunlight is blocked by objects.
Photograph 8.6 A rainbow
Science Exploration Did you know that shadow puppets use the concept that shadows are formed when light is blocked?
Photograph 8.8 Shadow puppets
8.2 1. Hisyam’s shadow is the shortest in the when the Sun is 2. The diagram shows two opaque objects blocking the light from a torchlight. Draw the shape of the shadow that will be formed on the screen.
his head. Screen
Wooden blocks
8.3
Reflection of Light
Let’s learn • • • •
State the characteristics of the image formed by a plane mirror. Communicate about the Law of Reflection. Draw ray diagrams to show the reflection of light Solve problems in daily life with the application of reflection of light.
Y
ou have learned how an image is formed in a plane mirror using the concept of reflection. Do you still remember the characteristics of the image? What are the other characteristics of the image formed by a plane mirror? 230
Bab 8 8 Chapter
Cahaya dan Chapter 8: Light Optik andPenyiasatan Optics Pengenalan kepada Saintifik
Table 8.1 shows the characteristics of the image formed by a plane mirror. Table 8.1 Characteristics of the image formed by a plane mirror
(b) Object size, H = Image size, h (c) Object distance, = image distance, OA OB
(a) Upright
Boy
Image
H
h OA
(d) Laterally inverted Object
(e) Virtual
Image
BB OA
OB
The image formed by a plane mirror is: • upright • laterally inverted • same size as the object • virtual • of the same distance as the object distance
Object
OB
Virtual image
Law of Reflection When a beam of light is directed onto a piece of a plane mirror at a certain angle (angle of incidence, i), the light ray will be reflected to a certain angle (angle of reflection, r). What is the relationship between the angle of incidence and angle of reflection? Carry out Experiment 8.1.
Experiment
8.1
Problem statement: What is the relationship between the angle of incidence, i and angle of reflection, r? Hypothesis: The angle of incidence, i is the same as the angle of reflection, r. Aim: To determine the relationship between the angle of incidence, i and angle of reflection, r White paper Variables Manipulated variable: Angle of incidence, i Responding variable: Angle of reflection, r Constant variable: The size of slit
Materials and Apparatus: Plane mirror, ray box, power supply, white paper, protractor.
Plane mirror
Slit
i
r
Normal line Ray box
Procedure Figure 8.12 1. Carry out this activity in the dark. 2. Arrange a ray box and a plane mirror on a sheet of white paper. 3. Direct the light beam towards the plane mirror at an angle i = 10°. 4. Measure the angle of reflection, r. 5. Repeat steps 3 and 4 with angle of incidence, i = 20°, 30°, 40° and 50°. Chapter Bab 8
231
6. Record your results in a table. Results Angle of incidence, i (°) Angle of reflection, r (°) 10 20 Conclusion Is the hypothesis accepted? What is the relationship between the angle of incidence, i and angle of reflection, r? Light reflected obeys the Law of Reflection: a. The incident ray, the reflected ray, and the normal line all lie on the same plane. b. The angle of incidence, i is equal to the angle of reflection, r. Normal line Incident ray Reflected ray i
r
The angle of incidence, i is equal to the angle of reflection, r. i=r
Plane mirror
Figure 8.13 Reflection of light
Science Exploration
Applications of Reflection of Light
Photograph 8.9 An ambulance
Photograph 8.10 Applications of reflection of light
8.3
Have you ever wondered why the word “ambulance” is written in an inverted manner? How is the image formed when the drivers of other vehicles look into their rear view mirror? Think about it.
1. Explain the Law of Reflection with the help of a light reflection ray diagram. 2. Complete the statement below. , , The image formed by a plane mirror is with the object distance. image distance is 232
Bab 8 8 Chapter
and the
Cahaya dan Chapter 8: Light Optik andPenyiasatan Optics Pengenalan kepada Saintifik
8.4
Refraction of Light
Let’s learn • Generalise that refraction occurs when light moves through medium of different densities. • Draw ray diagrams to show refraction of light when light propagate from one medium to another medium of a different density. • Generalise the relationship between the angle of incidence, i and angle of refraction, r, when light travels from a medium of low density to a medium of high density. • Justify the applications of refraction of light in daily life.
Why does a deep pond appear to be shallower and the fish in the pond appears to be much closer to the water surface?
Photograph 8.11 Fish in the pond
Why does a pencil look bent in a glass of water?
Photograph 8.12 A pencil looks bent
The illusions above occur as a result of the change in the direction of movement of light when light travels through two mediums of different densities. This phenomenon is known as refraction of light. Can you give examples of other refraction of light?
Chapter Bab 8
233
Observer
Light Image seen
Fish appears to be much shallower than its real location due to the refraction of light. 21
CPS
B
Actual location of fish
Due to the refraction of light phenomenon, how do you catch fish in a river?
Figure 8.14 Fish in an aquarium
Figure 8.15 shows the refraction of light when light rays pass through mediums of different densities. Normal
Normal Incident ray
Incident ray Air (less dense) Water (more dense)
Water (more dense) Air (less dense)
Refracted ray
Refracted ray
The light ray is refracted away from the normal when the incident ray moves from a more dense medium to a less dense medium.
The light ray is refracted towards the normal when the incident ray moves from a less dense medium to a more dense medium.
Normal Incident ray
Refracted ray
Normal
Water (more dense) Air (less dense)
The light ray is not refracted when the incident ray is parallel to the normal and moves from a more dense medium to a less dense medium.
Incident ray
Refracted ray
Bab 8 8 Chapter
Water (more dense)
The light ray is not refracted when the incident ray is parallel to the normal and moves from a less dense medium to a more dense medium.
Figure 8.15 Ray diagrams to show refraction of light 234
Air (less dense)
Cahaya dan Chapter 8: Light Optik andPenyiasatan Optics Pengenalan kepada Saintifik
Experiment
8.2
Problem statement What is the relationship between the angle of incidence, i and angle of refraction, r when light travels from a less dense medium to a more dense medium? Hypothesis: The greater the angle of incidence, i, the bigger the angle of refraction, r. Aim: To determine the relationship between angle of incidence, i and angle of refraction, r when light travels from a less dense medium (air) to a more dense medium (glass block) Variables Manipulated variable: The angle of incidence, i Responding variable: The angle of refraction, r Constant variable: The size of the slit, the shape of glass block Materials and apparatus: Glass block, ray box with single slit plate, plastic ruler, power supply, white paper, protractor. Procedure 1. Carry out this experiment in the dark. 2. Place a glass block on a white paper and trace its outline. 3. Direct a single incident ray onto the block, mark its path and draw its incident ray with a ruler. 4. Mark the path of the ray emerging from the block and draw the ray with a ruler. 5. Remove te block, connect the entry and exit points to show the path of the ray inside the block. 6. Draw a normal line at the entry point. 7. Measure the angle of incidence, i and the angle of refraction, r using a protractor. 8. Repeat steps 3 to 7 for different angles of incidence. 9. Record your results in a table.
White paper Glass block
r i
Slit
Ray box
Figure 8.16
Results Angle of incidence, i (°)
Angle of refraction, r (°)
Discussion 1. Plot a graph of i against r. 2. Based on the graph of the angle of incidence, i against the angle of refraction, r, what is the relationship between the angle i with the angle r? Conclusion Can the hypothesis be accepted? Chapter Bab 8
235
Question What happen to the light ray when it travels from a (a) less dense medium to a more dense medium? (b) more dense medium to a less dense medium? We can see many examples of the effects of light refraction in our daily life. Let us carry out Activity 8.6 to discover even more light refraction phenomena.
8.6 Aim: To investigate the phenomenon of refraction of light Instruction 1. Work in groups. 2. Use resources such as the library, Internet, and others to collect information regarding the following phenomena. • A spoon looks bent in water • The bottom of a pool appears to be shallower 3. Present the outcomes of your research in class.
8.4 1. Why does the bottom of a deep swimming pool appear shallower? 2. Light rays refract at a certain angle in two different cases as below. Differentiate the density of the two mediums for both the cases below. Case 1:
Case 2: A
C
B
D
8.5
Dispersion of Light
Let’s learn • Communicate about the dispersion of light. • Explain the dispersion of light in daily life with examples.
D
o you know why the components of colour in a rainbow can be seen when light passes through a glass prism (Figure 8.17)?
White light consists of seven components of colour. Each component of colour travels at a different speed in a medium. For example, red light has the highest speed, so red light is refracted the least. However, violet light has the lowest speed, so violet light is refracted the most. 236
Bab 8 8 Chapter
Cahaya dan Chapter 8: Light Optik andPenyiasatan Optics Pengenalan kepada Saintifik
1 When a white light ray is directed to a prism, the white
B
light will be separated into its components of colour. This is because the different colours in the white light bend towards the normal at different angles when entering the prism.
What will happen if a second inverted prism is placed behind the first prism? 21
CPS
2 When the different colours leave No
rm
White light
al
Glass prism
S P E C T R U M
the glass prism, they are refracted away from the normal. The different colours are dispersed in an order that is known as a spectrum. The spectrum of white light consists of red, orange, yellow, green, blue, indigo and violet colour.
Figure 8.17 Dispersion of white light by a glass prism
When sunlight enters rain droplets in the sky, the white light will be refracted and dispersed into seven different colours to form a rainbow.
Figure 8.18 The formation of rainbow Chapter Bab 8
237
8.7 Aim: To study the dispersion of light passing through a glass prism and the formation of rainbow Materials and Apparatus: Glass prism, white screen, ray box, a plane mirror, water, torch light, a piece of white paper, a basin, cellophane tape, a round black cardboard. Instruction I
Dispersion of light by a glass prism ght
te li
Whi
Glass prism White screen
Ray box
Figure 8.19
1. Carry out this activity in the dark. 2. Direct a narrow light ray from a ray box towards a glass prism (Figure 8.19). Adjust the glass prism slowly until a sharp colour spectrum is formed on a white screen. 3. Identify the colours formed on the white screen. 4. Observe the order of colours on the white screen. 5. Record your observation. Torch light
II Formation of a Rainbow
Black 1. Fill a basin half-full with water. cardboard White 2. Place a piece of mirror in the water with paper an incline on the side of the basin. Secure the mirror using a cellophane tape. Cellophane 3. Make a small hole on a piece of round black tape cardboard. Then, attach the cardboard Mirror to the front of a torch light. 4. Shine the torch light towards the mirror (Figure 8.20). Figure 8.20 5. Hold a white paper beside the mirror. Adjust the direction of the torch light until you see a rainbow on the paper.
8.5 1. List the seven colours formed on the screen below in the correct order. t 2. State the colour component that is refracted the most ligh hite W and refracted the least in the phenomenon above. Relate the phenomenon with the speed of each Glass prism Ray box White screen colour component. 238
Bab 8 8 Chapter
Cahaya dan Chapter 8: Light Optik andPenyiasatan Optics Pengenalan kepada Saintifik
Scattering of Light
8.6 Let’s learn
• Communicate about scattering of light. • Explain scattering of light in daily life with examples.
W
hy does the sky appear blue at midday and reddish in the evening?
Photograph 8.13 The phenomena of scattering of light
The two natural phenomena are caused by the scattering of light. Scattering of light occurs when light is reflected in all directions by clouds or particles in the air.
During midday
Blue light is scattered by particles in the air
Air particles and dust
During midday, blue light is scattered the most in all directions by the tiny particles in the atmosphere. Therefore, the sky looks blue during midday.
Earth
Figure 8.21 Scattering of light during midday Chapter Bab 8
239
During sunset During sunset, the sun is at the horizon. Red and orange light are less scattered and will go through the atmosphere to reach your eyes. Other coloured lights such as blue light are scattered away. Therefore, the sky looks reddish during sunset.
Air particles and dust Blue light scattered by the air particles Light directly from the Sun appears red Earth
Figure 8.22 Scattering of light during sunset
8.8 Aim: To study the scattering of light Materials and apparatus: Milk powder, 1000 ml glass beaker, ray box, white screen. Instruction 1. Carry out this activity in the dark. 2. Set up the apparatus as shown in Figure 8.23. 3. Turn on the ray box. 4. Add a few tablespoons of milk powder into the water. Stir the water until you can see a beam of light that shines through the mixture. 5. See the light beam from the side of the beaker. Then, look at the white screen as shown in Figure 8.23. 6. Add more milk powder and observe the colour change of the white light beam at the side of the beaker and on the white screen. 7. Record your observation. Milk powder Ray box
White screen Water
Figure 8.23
Questions: 1. What is the function of adding milk powder into the water? 2. What is the difference between the beam of light as seen from the side of the beaker and the beam of light on the screen? Explain your answer. 240
Bab 8 8 Chapter
Cahaya dan Chapter 8: Light Optik andPenyiasatan Optics Pengenalan kepada Saintifik
8.6 1. Why does scattering of light occur? 2. Fill the blanks with the correct words. (a) Sun
(b)
Atmosphere Sun
Observer during the day
Blue colour is scattered compared to red colour.
8.7
Observer during sunset
Red colour is scattered compared to blue colour.
Addition and Subtraction of Light
Let’s learn • • • • • •
Identify primary colours. Identify the addition of primary colours to produce secondary colours. Communicate about subtraction of light. Record the colours formed on the screen when light passes through colour filters. Differentiate the addition and subtraction of light. Explain addition and subtraction of light in daily life with examples.
C
oloured lights can be categorised into two types, namely primary colour and secondary colour. The primary colour is the basic colour that cannot be produced through colour mixing. Red, blue and green are primary colours.
Red Yellow Magenta White Putih
The Addition of Light What is the colour produced when two primary colours are mixed? Colours produced from the mixing of two colours are known as secondary colours. Cyan, yellow and magenta are secondary colours. White colour is produced when all the three primary colours are mixed together (Figure 8.24). What is the method to produce secondary colours? Let us carry out Activity 8.9 to produce secondary colours using colour filters. The addition of light http://www.physicsclassroom.com/class/light/ Lesson-2/Color-Addition
Green
Cyan
Blue
Figure 8.24 The addition of light
Formula for colour addition Primary + Primary = Secondary colour colour colour Red (R) Blue (B) Magenta (Mag) Red (R) Green (G) Yellow (Y) Blue (B) Green (G) Cyan (C) Red + Blue + Green = White Chapter Bab 8
241
8.9 Aim: To study the addition of primary colours to produce secondary colours Materials and apparatus: Primary colour filters, three ray boxes, white screen. Instruction 1. Carry out this activity in a dark room. 2. Prepare three ray boxes with red, blue and green filters each fixed in front of them. 3. Direct the red ray and green ray to overlap on a white screen as shown in Figure 8.25. What is the colour that you observe where the rays overlap? White screen Green filter Ray box Red filter Power supply
Figure 8.25
4. Repeat step 3 using green and blue rays, followed by red and blue rays. Observe the colours formed.
The Subtraction of Light How do we see the colour of opaque objects? Why do we see banana as yellow, strawberry as red and leaf as green? The light which has the same colour as the colour of the opaque objects will be reflected directly into our eyes, while the light of other colours will be absorbed by the objects. This phenomenon is known as subtraction of light.
Green
Yellow
Red
Photograph 8.14 Colour of fruits 242
Bab 8 8 Chapter
Cahaya dan Chapter 8: Light Optik andPenyiasatan Optics Pengenalan kepada Saintifik
The Principle of Light Subtraction The colour of opaque objects depends on the colour of the light reflected into our eyes. Objects with primary colours (red, blue or green) will only reflect the light which has the same colours as them. White light
Green object
A green object only reflects green light. Other coloured lights will be absorbed. Therefore, the object appears green.
Objects with secondary colours (yellow, magenta or cyan) reflect the light of the same colour and also the light of primary colours which form the secondary colour. White light
A yellow object reflects yellow, red and green colours. The overlap of red and green lights causes the object to appear yellow.
Yellow object
White objects appear white in white light because the white objects reflect all colours in white light. White light
White object
White objects reflect all colours in white light. All coloured lights overlap to produce white light again.
Black objects appear black because they absorb all colours in white light.
White light
Black objects absorb all colours in white light. No coloured lights are reflected. Therefore, the objects appear black.
Black object
Chapter Bab 8
243
Usually, colour filters are used to understand the principle of subtraction. There are two types of colour filters: Primary colour filters
Secondary colour filters
• Allow only the light of the same colour to pass through, light of other colours are absorbed.
• Allow only the light of the same colour and the light of primary colours which form the secondary colour to pass through. Light of other colours are absorbed.
Red light
White light Red filter
Green light
White light
Yellow filter Red light Blue light Magenta light Magenta filter
Green filter
White light Blue light
White light
Red light Green light Yellow light
White light
Blue filter
Blue light Green light Cyan light
White light Cyan filter
Let us study the subtraction of light when light is absorbed or subtracted by colour filters in Activity 8.10. 21
B ICS
What will happen if a second colour filter is placed at the back of the first colour filter?
8.10 Aim: To study subtraction of light Materials and apparatus: Primary colour filters, secondary colour filters, ray box, white screen. Instruction White screen
Ray box
Secondary colour filter Primary colour filter
Figure 8.26 244
Bab 8 8 Chapter
Cahaya dan Chapter 8: Light Optik andPenyiasatan Optics Pengenalan kepada Saintifik
1. Carry out this activity in a dark room. 2. Direct a white light beam towards a white screen. 3. Place a primary colour filter of red and secondary colour filter of yellow in front of the ray box (Figure 8.26). What can you observe on the white screen? 4. Repeat step 3 by replacing the secondary colour filter of yellow with a magenta and cyan filter. 5. Record your results in the table below. 6. Repeat steps 3 to 5 by replacing the primary colour filter of red with green and blue filters. Primary colour filter
Secondary colour filter
Colour of light on the screen
Yellow Red
Magenta Cyan Yellow
Green
Magenta Cyan Yellow
Blue
Magenta Cyan
Difference between Addition and Subtraction of Light After learning about addition and subtraction of light, what is the difference between them? Addition and subtraction of light are two different principles of light. The addition of light is the mixing of primary colour lights to produce secondary colour lights. However, subtraction of light occurs when an opaque object reflects the light of same colour and absorbs the light of other colours.
Chapter Bab 8
245
Examples of Addition and Subtraction of Light Example 1
Colour television
Photograph 8.15 A colour television
Example 2
Coloured lights on stage
Photograph 8.16 Coloured lights play a role on the stage during a performance
Example 4 Example 3
Coloured lights in a stadium
Photograph 8.17 Coloured lights in a stadium 246
Bab 8 8 Chapter
Coloured lights at KLCC
Photograph 8.18 Coloured lights in the fountain in front of KLCC
Cahaya dan Chapter 8: Light Optik andPenyiasatan Optics Pengenalan kepada Saintifik
8.11
21
ICS
Aim: To gather the information regarding examples of addition and subtraction of light Instruction 1. Work in groups. 2. Each group has to find information regarding examples of addition and subtraction of light. 3. Present your findings using multimedia presentation.
8.7 1. Three torchlights are switched on as in the diagram below. What are the colours formed in A, B, C and D? Red
A
D
C
B
Green
Blue
2. State the colours of the light formed on the screen in the diagrams below. (a)
(b)
Red filter
Colour:
White light
Green filter
(c)
Screen
Screen Colour:
White light Magenta filter White light
Screen Colour:
Chapter Bab 8
247
248
Bab 8 8 Chapter
The usage of plane mirror, concave mirror and convex mirror in daily life
Characteristics of image formed by a plane mirror, concave mirror and a convex mirror
Convex mirror
Concave mirror
Plane mirror
The use of mirrors
Formation of shadow
Travels in straight lines
Appearance of lightning before thunder
Travels fast
Properties of light
Application of refraction of light Examples of dispersion of light Examples of scattering of light
Dispersion of light Scattering of light
Application of reflection of light
Law of reflection
Refraction of light
Reflection of light
Phenomena of light
Light and Optic
Occurs when light is reflected or absorbed
Subtraction of light
Using primary colours to produce secondary colours
Addition of light
Secondary colour
Primary colour
Addition and subtraction of light
Cahaya dan Chapter 8: Light Optik andPenyiasatan Optics Pengenalan kepada Saintifik
After learning the chapter, you are able to: 8.1 The Use of Mirrors Differentiate between a real image and a virtual image. Communicate about the characteristics of image formed by a plane mirror, concave mirror and convex mirror. State that the object distance is equal to the image distance in a plane mirror. Use the plane mirror to apply the concept of reflection of light. Justify the application of concave mirrors and convex mirrors in daily life. Construct an optical instrument to appreciate the use of these optical instruments to enhance the ability of the human senses. Solve problems in daily life involving the application of plane mirrors, concave mirrors and convex mirrors. 8.2 Properties of Light Communicate about the properties of light. 8.3 Reflection of Light State the characteristics of the image formed by a plane mirror. Communicate about the Law of Reflection. Draw ray diagrams to show the reflection of light. Solve problems in daily life with the application of reflection of light. 8.4 Refraction of Light Generalise that refraction occurs when light moves through medium of different densities. Draw ray diagrams to show refraction of light when light propagate from one medium to another medium of a different density. Generalise the relationship between the angle of incidence, i and angle of refraction, r, when light travels from a medium of low density to a medium of high density. Justify the applications of refraction of light in daily life. 8.5 Dispersion of Light Communicate about the dispersion of light. Explain the dispersion of light in daily life with examples. 8.6 Scattering of Light Communicate about scattering of light. Explain scattering of light in daily life with examples. 8.7 Addition and Subtraction of Light Identify primary colours. Identify the addition of primary colours to produce secondary colours. Communicate about subtraction of light. Chapter Bab 8
249
Record the colours formed on the screen when light passes through colour filters. Differentiate the addition and subtraction of light. Explain addition and subtraction of light in daily life with examples.
Summative Practice
8
1. What are the differences between a real image and a virtual image? 2. Circle the correct refracted light ray. Source of light
Normal line
Air Glass A
B
C
D
Figure 1
3. Which observer will see the sunlight as reddish? Sun Z Y
Earth
X
Figure 2
4. Write the colour produced when the following colour lights are mixed. (a) Red light + Blue light → (b) Red light + Green light → (c) Blue light + Green light → (d) Red light + Blue light + Green light → 5. A periscope is built using two plane mirrors. State the characteristics of the image that can be seen by the observer. 250
Bab 8 8 Chapter
45°
Figure 3 45°
Mirror
Mirror
Cahaya dan Chapter 8: Light Optik andPenyiasatan Optics Pengenalan kepada Saintifik
6. The following statement explains the side mirror of a car: Objects in the mirror appear closer than the actual distance. What is the type and function of the side mirror of the car as shown in Photograph 1?
Photograph 1
7. Draw a ray diagram to show why the feet of the boy appears short in Figure 4.
Figure 4
8. Kavita saw a rainbow at a fountain in a park. What is the phenomenon that has occurred?
Photograph 2
9. Akmal wants to fix mirrors in every corner of his shop so that he can view every corner to ensure that his things are not stolen. He is given three mirrors as below. Which mirror should Akmal choose? Give a reason.
P
Q
R
Figure 5 Chapter Bab 8
251
10. A man wants to see what is behind a wall as in Figure 6. Suggest an instrument to help the man to see what is behind the wall. Draw the instrument.
Wall
Figure 6
11. Khairul is learning how to spear a fish in a river. Even though he has tried many times, he is still unable to do so. Based on the diagram below, what phenomenon has occurred? How can you help Khairul to spear the fish? Explain.
Image of fish Fish Figure 7
12. An adventurer has lost his way in a jungle. He lost his watch. Suggest an instrument that can help him to estimate time accurately. Explain the property of light used in creating the instrument. Draw the instrument.
252
Bab 8 8 Chapter
Bumi 9: Earth Chapter Pengenalan kepada Penyiasatan Saintifik
5
h Exploration of Eart and Space EST LAT MENTS LOP CE E V IEN DE C S IN
The Earth supplies us with useful fossil materials. For example, fossil fuel is very useful in transportation and in our everyday life. What are fossil materials? Chapter Bab 9
253
Chapter
9
Earth
What is the shape of Earth? What are the layers of atmosphere? What are the processes that cause changes of shapes on the Earth’s surface? What are the geohazard phenomena that occur as a result of the internal changes of the Earth? What are the Earth's resources and applied geology?
Let’s study: The System and Structure of Earth Composition of Earth Main Processes of Earth 254
Bab 9 9 Chapter
Geohazard Phenomena Age of Earth Earth's Resources and Applied Geology
Bumi 9: Earth Chapter Pengenalan kepada Penyiasatan Saintifik
N
I T E L L U B E C N SCIE AT?
ERICAL OR FL
IS EARTH SPH
horizon. The n we look at the he w t rdinand fla s ok lo though it was proven by Fe e ap sh in al ric arth is spherical sphe man ates that Earth is pointed a Malay ber 1519. He ap hypothesis that st em Even pt r. Se to la in n ns ai tra ck” as his sail from Sp la t B se e th ho w ry n en la el “H Mag ang or his crew's voyage med Panglima Aw in 1521, his and es in pp from Malacca na ili Ph e th was killed in though Magellan shape. rth is spherical in Ea had proved that
E
Atmosphere Hydrosphere Biosphere Geosphere Ozone depletion
Geological time Igneous rock Metamorphic rock scale Fossil Sedimentary rock Surface water Exogenic process Underground water Endogenic process Minerals Geohazards Hydrothermal
Chapter Bab 9
255
9.1
The System and Structure of the Earth
Let’s learn • Communicate about the system of the Earth. • Explain the differences of the Earth's layers based on its composition and physical characteristics. • Realise that Earth is the only place that can sustain life based on its physical characteristics.
H
ave you ever thought about the structure of the Earth? What are the layers of air above the Earth? How is water on Earth such as oceans, rivers, clouds and lakes distributed? What are the Earth’s layers and its composition? Why is Earth suitable for living things? The Earth system consists of four main components which are interconnected, namely atmosphere, biosphere, hydrosphere and geosphere.
Video on atmosphere's structure and composition of air
Atmosphere Hydrosphere Water zone that includes rivers, lakes, seas and also water trapped as ice, underground water and water vapour in the atmosphere.
Air zone covering the Earth’s surface.
Rock and soil zone on the Earth’s surface. Life zone consists of a variety of life such as humans, animals, plants and microorganisms.
Biosphere
Geosphere Photograph 9.1 The Earth system consists of four main components 256
Bab 9 9 Chapter
Bumi 9: Earth Chapter Pengenalan kepada Penyiasatan Saintifik
Atmospheric Stratification
Earth’s atmosphere consists of five layers, each with its respective roles. Exosphere layer (480 km and above) • Contains light gases such as helium and hydrogen. • Air becomes thinner towards space. • Communication satellites orbiting Earth in this layer allow phone calls and television broadcasts.
Exosphere
Thermosphere layer (80 – 480 km) • Also known as the ionosphere because it contains ions that can reflect radio waves. • Aurora, a stream of colourful lights resulting from reactions of charged particles with Earth’s magnetic field and atmospheric gases occurs here.
Thermosphere
Mesosphere
Mesosphere layer (50 – 80 km) Burning and destruction of meteorites occur in this layer.
Stratosphere Ozone layer
Troposphere
Stratosphere layer (13 – 50 km) • This layer is suitable and stable for aircraft flights. • The ozone layer that contains ozone gas which absorb harmful ultraviolet rays from sunlight is found here. • The ozone layer depletes when chlorofluorocarbons (CFCs) released from pesticides, refrigerators and air-conditioners break down ozone molecules in the ozone layer.
Troposphere layer (0 – 13 km) The layer where living organism breathes, wind blows and where clouds, rain and snow form.
Figure 9.1 Atmospheric stratification
Chapter Bab 9
257
50
What do you feel when a climbing mountain? Will you feel cold and have difficulties in breathing? Altitude (km)
From troposphere to stratosphere, the altitude increases. The higher the altitude, the lower the air pressure. The temperature also becomes lower when altitude increases.
Standard pressure at sea level (101,325 Pa)
40 30 20
Stratosphere (13 – 50 km)
Aeroplane
10
Troposphere (0 – 13 km) 0
20,000
40,000 60,000 80,000 Air pressure (Pa)
100,000 120,000
Figure 9.2 Relationship between air pressure and altitude
Ocean Stratification
The ocean can also be divided into different zones, from a zone where light can penetrate to a zone where light cannot penetrate (dark zone) (Figure 9.3). Depth (m) Sun Sea level
0 Surface zone
50 100 200
Midnight zone
500 1,000 1,500
Dark zone
2,000
Surface zone In this zone, the water is very shallow and light can penetrate. This makes the zone suitable as a habitat for plants. Midnight zone This zone has little or no light. It is difficult for plants to live at this depth but this level of depth becomes the habitat for large marine animals, such as giant squids and various species of whales.
3,000 4,000 5,000 10,000
Figure 9.3 Ocean stratification 258
Bab 9 9 Chapter
Dark zone This zone is very deep and no light can reach it. Therefore, most animals in this zone have shimmering bodies or are able to glow in the dark.
Bumi 9: Earth Chapter Pengenalan kepada Penyiasatan Saintifik
Distribution of Water on Earth The ocean contains a lot of water. Where does this water come from? Seawater is evaporated by sunlight and is taken to the mainland by clouds before it falls back as rain water. The water in the rivers then flow into the ocean. The water cycle process is continuous. Therefore, it is said that the total amount of water contained in Earth, on Earth’s surface and in Earth’s atmosphere is always constant.
The Water Cycle Cloud
Water in the atmosphere
Water in ice and snow
Condensation Rain Evaporation Water flowing on the surface
Water flows into the river
Water seep into the ground
River flow
Evaporation
Spring Dis
ch
arg
Evaporation
eo
Fresh water storage fg
rou
nd
wa
Water in the ocean
ter
Water storage underground
Figure 9.4 The water cycle
9.1
21
ICS
Aim: To prepare a multimedia presentation on atmospheric stratification and ocean stratification Instruction 1. Work in groups. 2. Each group is required to do a presentation regarding one of the topics below: • Atmospheric stratification and its role • Ocean stratification and the distribution of animals in it • Ozone depletion • Distribution of water on Earth
Chapter Bab 9
259
Earth's Layers Earth can be divided into three main layers according to its physical properties, namely crust, mantle and core. The mantle consists of the lithosphere, asthenosphere and mesosphere. Lithosphere covers the crust and the top part of the mantle.
Crust
Lithosphere Asthenosphere
Mantle
Mesosphere
Outer core Inner core
Figure 9.5 The Earth's main layers
9.2 Aim: To create a model of Earth Instruction 1. Work in groups. 2. Design a model of Earth containing four layers using clay. 3. Present your model in class.
9.3 Aim: To discuss the differences in Earth's layers based on its composition and physical characteristics Instruction 1. Work in groups. 2. Gather information about the composition and physical characteristics of each of the Earth's layers. 3. Present your findings using a multimedia presentation.
260
Bab 9 9 Chapter
Bumi 9: Earth Chapter Pengenalan kepada Penyiasatan Saintifik
Earth is the Only Home for Living Organisms Recall the topic of Solar System that you have learned in primary school. Earth is the third planet from the Sun and is the only planet suitable for life in our Solar System (Photograph 9.2). One of the unique characteristics of Earth that makes it suitable for all life is the Earth’s temperature, which is not too hot or too cold compared to other planets. This is due to the Earth’s position, which is not too near or too far from the Sun. Besides, the presence of water and oxygen on Earth also allows Earth to host all life. Therefore, love our Earth by taking good care of the environment!
Photograph 9.2 Scientists are searching for another habitable planet for all life so that we can move to that planet in future.
9.1 1. Earth consist of four main spheres which are . and
,
,
2. A fish catches its prey using light. In which zone of the ocean can this fish be found? Why?
9.2
Composition of the Earth
Let’s learn • Explain the type and characteristic of rocks. • Communicate on how to differentiate the process of rock formation.
E
arth’s crust is formed from various types of rocks, which differ in colour, structure, texture and the way it is formed. Generally, the rocks can be categorised into three groups, namely igneous rocks, sedimentary rocks and metamorphic rocks. Each type of rock forms differently and takes thousands of years to form. All rocks contain materials known as minerals. Chapter Bab 9
261
Types and Characteristics of Rocks Table 9.1 shows the types of rocks and their characteristics. Table 9.1 Types of rocks and their characteristics
Igneous rock
Sedimentary rock
Metamorphic rock
Formed from the process of cooling and freezing of magma or lava that flows out of the mantle. Contains various minerals.
Formed by compression of deposited materials carried by the rivers, glaciers and wind.
Formed when igneous rocks or sedimentary rocks are exposed to very high pressure and temperature. Usually harder than the original rocks that formed them.
Consists of many layers which are sometimes hollow and contain fossils.
The Process of Rock Formation
ift urfa ce
Upl
to s
Sedimentation of eroded materials a d ssio m g n re u s res Heat and p Sedimentary rocks Metamorphic g n i t l rocks Me
Co fre ez olin g ing of an m a
Heat and pressure increases
ion
Magma
os
Video on classification of rocks
Igneous rocks
d an at ure He ess pr
Weathering
Er
How are igneous rocks, sedimentary rocks and metamorphic rocks formed? The process of rock formation can be explained using the rock cycle as shown in Figure 9.6.
Com
pre
Figure 9.6 The rock cycle
9.2 1. How are sedimentary rocks, igneous rocks and metamorphic rocks formed? Explain. 2. Why are fossils not found in igneous rocks? 3. Why are metamorphic rocks harder than igneous rocks and sedimentary rocks? 262
Bab 9 9 Chapter
Bumi 9: Earth Chapter Pengenalan kepada Penyiasatan Saintifik
9.3
Main Processes of the Earth
Let’s learn • Explain the different Earth processes that affect the changes on Earth. • Communicate about exogenic and endogenic processes.
W
hat are Earth’s processes that cause changes on Earth’s surface? How do the changes take place? Earth’s surface is formed by two processes, namely exogenic process and endogenic process. Exogenic Process
• Process that occurs on Earth’s surface. • Examples: Weathering, erosion, mass and land depletion, transport and sedimentation. Erosion It is a process of eroding of the Earth’s surface by moving agents such as water, wind and waves.
Weathering It is a process of rock fragmentation and decomposition or decay due to changes in temperature, rainwater, frosting and microorganisms.
Mass and land depletion They involve soil movement from the top of a slope to below as a result of gravitational force.
Exogenic processes
Transport and sedimentation Weathered or corroded materials are moved by agents such as running water, wind, waves and glaciers. The materials will be sedimented when the velocity of the agents decreases. Figure 9.7 Exogenic processes Chapter Bab 9
263
• Process that is caused by forces from within the Earth. • Forms and changes the Earth’s surface. • Examples: Mantle convection process, magma activity and Earth's crust movement (Plate Tectonics).
Endogenic Process
Lithosphere
Mantle
Outer core Inner core
Mantle convection process The high temperature in the mantle and the core of Earth produces convection currents in the asthenosphere layer. These currents are able to move Earth’s crust.
Earth's crust movement (Plate Tectonics) According to the theory of Plate Tectonics, the Earth’s crust is divided into several pieces of plates. These plates constantly move resulting in collision and divergence which produce various landforms on Earth and continental drifts.
Endogenic processes
Divergence of Earth's crust
Magma activity Volcano is a vent on the Earth’s crust that allows molten and hot magma to flow out through it in a strong eruption. The erupted materials accumulate around the slope of the vent and form volcanic cones.
Figure 9.8 Endogenic processes 264
Bab 9 9 Chapter
Bumi 9: Earth Chapter Pengenalan kepada Penyiasatan Saintifik
9.3 1. What are exogenic and endogenic processes? 2. What are the agents causing erosion? 3. What is Plate Tectonics theory? 4. Explain mantle convection process.
9.4
Geohazard Phenomena
Let’s learn • Communicate about geohazards. • Generate ideas on the importance of science and technology to prepare for geohazards. • Realise that environmental disasters affect human livelihood.
A
fter learning the exogenic and endogenic processes in subtopic 9.3, do you know the consequences of the endogenic process? The consequences of the endogenic process are occurrence of geohazards such as earthquake, landslide, tsunami and volcanism. Can you identify each of these geohazards?
Tsunami Volcanism
Global warming
Earthquake
Landslide
Sinkhole
Video on preparing for earthquakes
Photograph 9.3 Geohazards Chapter Bab 9
265
Quicksand is a geohazard that usually occurs in wetlands while acid rain is a geohazard that usually occurs in the industrial area.
Quicksand
Acid rain
Figure 9.9 Quicksand and acid rain
9.4 Aim: To gather information about geohazards Instruction 1. Work in groups. 2. Gather information on how these geohazards happen. (a) Earthquake (d) Tsunami (g) Quicksand (b) Landslide (e) Global warming (h) Sinkhole (c) Volcanism (f) Acid rain 3. Present your findings using a multimedia presentation.
Science and Technology Used to Prepare for Geohazards Advances in science and technology allow the invention of devices that could provide early warnings on occurrence of landslide and tsunami. Transducer Acoustic sensor Steel waveguide
I am placed on the slope of hills to give early warnings of landslides.
Gravel backfill Deforming slope generates acoustic emission from gravel
Figure 9.10 The device to detect landslides
I am placed at the shoreline to give early warnings of tsunami via satellite. Photograph 9.4 The device to detect tsunami in Malaysia
Can you think of other inventions used to predict or provide early warnings of geohazards? 266
Bab 9 9 Chapter
Bumi 9: Earth Chapter Pengenalan kepada Penyiasatan Saintifik 21
The Impact of Geohazards
ICS
Geohazards such as tsunami and earthquake can cause loss of life, diseases, starvation and damage to properties. We should sympathise with and assist victims of environmental disasters.
nami waves
43 Malaysians killed by tsu
s who were hit by killed, including 43 Malaysian re we ple peo ny Ma ber world in the last 40 KUALA LUMPUR 26 Decem ay; the most powerful in the tod atra Sum rn the nor in e huge waves by the earthquak the tsunami. sions have been destroyed by years. Many homes and posses (Extracted and adapted from
Earthquake on Mount Kinabalu
Utusan Melayu, December 27,
2004)
Occurrence of mudslide
KOTA KINABALU: As a result of the earthquake, 19 people were killed. (Extracted and adapted from Mstar, June 23, 2015)
CAMERON HIGHLANDS – The installation method of plastic protective rain structure by farmers is one of the factors which trigger the occurence of mudslide.
(Extracted and adapted from Kosmo, March 4, 2016)
Visit the following websites to get more information about tsunami, volcano eruption, mud flood and the collapse of Highland Towers. Tsunami http://www.tsunami.noaa.gov/
A mud flood in Cameron Highlands http://www.beritasemasa.com. my/gambar-banjir-lumpur-dicameron-highland
Volcano eruption http://www.euronews/tag/ volcano-eruption
Collapse of Highland Towers https://en.wikipedia.org/wiki/ Highland_Towers_collapse
9.4 1. List three examples of geohazards. 2. What are the impacts of geohazards to humans? 3. State two devices invented by scientists to predict occurrences of geohazards. Chapter Bab 9
267
9.5
Age of Earth
Let’s learn • • • •
Communicate about geological time scale of the Earth. Explain the method to determine the age of the Earth. Communicate about fossils. Reason about the importance of fossils in the advancement of contemporary science.
The age of Earth is estimated to be 4.5 billion years based on meteorites obtained. Earth has gone through various stages of periods, which have changed or shaped the Earth’s landscape. Geologists define a long period of time as an era. Each era is divided into several periods.
Period
B
What era are we living in?
268
Bab 9 9 Chapter
Figure 9.11 Geological time scale
Era
Note M.Y. refers to million years.
Bumi 9: Earth Chapter Pengenalan kepada Penyiasatan Saintifik
Fossil Fossils are Earth's materials such as plants, animals and insects which have been submerged and buried for a very long period of time.
The word 'fossil' originates from the Latin word ‘fossilis’, which means ‘obtained from digging'.
Figure 9.12 Examples of fossils Dinosaur
The importance of fossils to current scientific development:
Flowering plants Human
Insect
Fish Origin of Earth
500
Jellyfish
Origin of life
5000 Seaweed
4000
1000
• Fossil records can provide information about how animals and plants species on Earth have evolved over millions of years. • Fossil records can also provide information about species that have gone extinct.
Million years
3000
2000
Bacteria
Protozoa
Figure 9.13 Various organisms on Earth since 5000 million years ago
9.5 1. When did fish first appear on Earth? 2. Between insects and flowering plants, which appeared on Earth first? 3. When did seaweeds first appear on Earth? Chapter Bab 9
269
9.6
Earth's Resources and Applied Geology
Let’s learn • • • • • •
Explain surface water and its risks. Explain the importance of underground water and its risks. Communicate about economic minerals. Explain the formation of petroleum and coal. Communicate about the hydrothermal process. Solve problems about the negative effects of unplanned human activities on all living things on Earth.
Surface Water and Underground Water What is surface water?
Surface water is found on the surface of Earth. Examples of surface water include seas, ponds and rivers.
Surface water can be polluted by waste materials from industrial and housing areas. Excessive fertilisers and pesticides from agricultural areas also pollute river water.
Photograph 9.5 Surface water Do you know that there is water under the ground known as underground water?
Yes, I do. Underground water or aquifer fills up the empty spaces between soil particles and the layers of permeable rocks.
Leaching of chemical fertilisers and pesticides in agriculture exposes underground water to the risk of pollution. Chemicals from industrial and domestic waste in landfills carry the risk of polluting underground water.
B
Do surface water and underground water interconnect? 21
Photograph 9.6 Underground water 270
Bab 9 9 Chapter
ICS
Bumi 9: Earth Chapter Pengenalan kepada Penyiasatan Saintifik
Economic Minerals Economic minerals in the Earth consist of metallic minerals, non-metallic minerals and rare earth minerals. Examples of metallic minerals are iron ore, tin and gold while examples of non-metallic minerals are coal and petroleum. Rare earth minerals consist of one or more than one of 17 rare earth elements found inside Earth's crust. Even though almost all rare earth minerals can be found in abundance, it is however not easy to separate them as they exist together with other rare earth elements. Because of the rare minerals' unique properties, they are very important in modern technology. They are used in computers, DVDs, communication devices, television and others. Therefore, technology based on rare earth minerals is very important to the development of the economy of the country and world in general.
Petroleum and coal are used as fuel. How are they formed? Coal
Millions of years ago, plants died naturally.
Under high pressure and heat, fossil of plants turned slowly into coal.
The remains were buried under layers of sediment and mud.
Figure 9.14 The formation of coal Fossils trapped Dead land organisms were buried underground.
Natural gas Mud and rocks
Sea
Seabed Dead marine organisms sank into the seabed.
Petroleum After millions of years, the dead organisms became more embedded into the earth below thick layers of stone and mud.
Through the action of bacteria, partial decomposition occured in a state of oxygen shortage. The continuous decomposition by bacteria under high temperature and pressure finally produced petroleum and natural gas.
Figure 9.15 The formation of petroleum and natural gas Chapter Bab 9
271
Hydrothermal Process Have you even been to a hot spring? Do you know why the water is hot? The water is heated naturally by the heat from the Earth. This is known as hydrothermal process. What are the advantages of the hydrothermal process in economic prospects?
Electricity generators
Well
Steam Hot steam is used to drive a turbine and generate electricity Hot water
Metamorphic rocks Heated aquifer
Metamorphic rocks
Heat source (magma)
Photograph 9.7 Hot spring in Sungai Klah, Perak
Figure 9.16 Formation of a hot spring and generation of electricity through the hydrothermal process
The Negative Effects of Unplanned Human Activities Human activities that are not well-planned may cause negative effects to all living things. Think of ways to solve them. Erosion Deforestation Agriculture Industrialisation Open burning
Flash flood Human activities that are not well-planned
Extinction of flora and fauna Water, air, thermal and sound pollution Global warming
Figure 9.17 Human activities that are not well-planned
272
Bab 9 9 Chapter
Bumi 9: Earth Chapter Pengenalan kepada Penyiasatan Saintifik
9.5 Aim: To debate how exploitation of Earth’s resources may cause adverse effects on living things Instruction 1. Work in groups. 2. The motion of the debate is 'Exploitation of Earth’s resources may cause adverse effects on living things'. 3. Each group is required to present their arguments.
9.6
21
ICS
1. What are the effects of deforestation? 2. Minerals mined from Earth are required for continuous economical development of a country. However, mineral supply is limited. Suggest ways to ensure the continuous supply of minerals.
My Malaysia The discovery of dinosaur fossils for the first time in Malaysia by a geologist from the University of Malaya shook our nation. The fossils were found in the Endau Rompin Forest, Pahang which is among the oldest jungles in the world. Can you identify the type of dinosaur shown below? Do you want to be a geologist to find more fossils?
Visit the following website for more information. The discovery of dinosaur fossils in Malaysia http://www.sciencedaily.com/releases/2014/02/140224204737.htm
Chapter Bab 9
273
274
Bab 9 9 Chapter
Geosphere
Biosphere
Distribution of water
Ocean stratification
Hydrosphere
Atmospheric stratification
Atmosphere
System of the Earth
Inner core
Outer core
Mantle
Crust
Earth's layers
Structure of the Earth
The process of rock formation
Types and characteristics of rocks
Composition of the Earth
Geohazard Phenomena
The impact of geohazards
Importance of fossils
Fossil
Method to determine the age of the Earth
Geological time scale
Age of the Earth
Mantle convection process
Magma activity
Earth crust movement (Plate Tectonics)
Endogenic process
Transport and sedimentation
Mass and land depletion
Science and technology Weathering used to prepare for Erosion geohazards
Exogenic process
Main Process of the Earth
Earth
Hydrothermal process
Economic minerals
Underground water and its risks
Surface water and its risks
Earth's Resources and Applied Geology
Bumi 9: Earth Chapter Pengenalan kepada Penyiasatan Saintifik
After learning this chapter, you are able to: 9.1 The System and Structure of the Earth Communicate about the system of the Earth. Explain differences of the Earth's layers based on its composition and physical characteristics. Realise that Earth is the only place that can sustain life based on its physical characteristics. 9.2 Composition of the Earth Explain type and characteristic of rocks. Communicate on how to differentiate the process of rock formation. 9.3 Main Processes of the Earth Explain the different Earth processes that affect the changes on Earth Communicate about exogenic and endogenic processes. 9.4 Geohazard Phenomena Communicate about geohazards. Generate ideas on the importance of science and technology to prepare for geohazards. Realise that environmental disasters affect human livelihood. 9.5 Age of the Earth Communicate about geological time scale of the Earth. Explain the method to determine the age of the Earth. Communicate about fossils. Reason about the importance of fossils in the advancement of contemporary science. 9.6 Earth's Resources and Applied Geology Explain surface water and its risks. Explain the importance of underground water and its risks. Communicate about economic minerals. Explain the formation of petroleum and coal. Communicate about the hydrothermal process.
Summative Practice
9
1. Figure 1 shows the various layers of the Earth. Label each layer with the correct name.
P: Q: R:
Figure 1
S: Chapter Bab 9
275
2. Weather phenomena such as rain, cloud, earthquake and storm form inside the Earth’s atmosphere. In which atmospheric layer do the phenomena occur? 3. Figure 2 shows the atmospheric layers. (a) In which layer does aurora occur? (b) State two living organisms that can be found in layer P. 4. What are the factors that influence the formation of metamorphic rocks? 5. Figure 3 shows flow of lava from a volcano. What rocks could form in P?
P Q R S T
Figure 2 Volcano Lava flow P
6. Salina found a type of rock by the mouth of a river. The characteristics of the rock were recorded as below. • Hollow • Layered • Contains dry fossil
Magma
Figure 3
What type of rock is it?
7. Uncle Yatim is a farmer. His son always advises him not to spray pesticides excessively. Why?
Figure 4
8. The statement below shows a human activity.
Deforestation of mangrove forests for timber creates negative consequences.
In your opinion, what negative consequences may arise due to the deforestation of mangrove forests? 276
Bab 9 9 Chapter
Bumi 9: Earth Chapter Pengenalan kepada Penyiasatan Saintifik
9. The statement below refers to one of the characteristics on the surface of Earth.
Water distribution on Earth is constant.
In your opinion, is the statement true? Discuss.
10. Earthquakes are recorded using sensitive seismographs that detect movements or vibrations. Invent a simple seismograph device for detecting vibration on Earth’s surface using marker, metal rod, spring, weight, cardboard paper and other easily obtainable objects. Drop heavy objects close to the device built to create your own “quake”.
11. The statement below shows a newspaper cutting regarding an issue that happened in Malaysia.
Bauxite pollution in Kuantan KUANTAN – Kuantan residents complain about the bauxite pollution in the vicinity of Bukit Goh, Gebeng and Kuantan Port which can cause health risks. Uncontrolled bauxite mining activity has dirtied the main road. The air is polluted by bauxite dust. The river is also polluted by bauxite mining. Bauxite is red soil rich in aluminum. Bauxite
(Extracted and adapted from Astro Awani, 5 July 2015)
In your opinion, what are the negative consequences due to uncontrolled bauxite mining in Kuantan? 12. Cameron Highlands always faces landslides. Suggest a suitable device that could detect the possibilities of a landslide.
Chapter Bab 9
277
ONLY SELECTED ANSWERS ARE PROVIDED HERE Chapter 1 Formative Practice 1.1 1. Growth of a baby, the occurrence of day and night 2. (a) observation, experiments (b) biology 3. Biology- Botanist, Chemistry- Pharmacist, Physics- Astronaut Formative Practice 1.2 1. (a) (b) (c) (d) 2. (a) (i) Poisonous/toxic (ii) Irritant (iii) Flammable (iv) Explosive (v) Corrosive (b) Mercury and chlorine 3. Inform his teacher. If possible, turn off the electrical supply. With the teacher’s help, use a suitable fire extinguisher to extinguish the fire. If he is not sure, he should leave the laboratory immediately. Formative Practice 1.3 1. Length – metre, m; Mass – kilogram, kg; Time – second, s; Temperature – kelvin, K; Electric current – ampere, A 2. (a) 13 cm (b) 0.018 kg (c) 4000000 µm (d) 24 kg (e) 6 mA ormative Practice 1.4 F 1. (a) 6.28 mm (b) 4.56 mm 2. 24 cm2 3. Value shows the mass of Chong Formative Practice 1.5 1. A = 2 g cm-3, B = 2 g cm-3, C = 2 g cm-3 2. Liquid R, the most dense liquid will sink to the bottom Formative Practice 1.6 1. Inference is the reason or cause for the observation of a phenomenon. 2. Manipulated variable = surface area of the container Constant variable = the initial volume of water in the container, surrounding temperature and
278
Answers
period of the experiment Responding variable = The quantity of water after 30 minutes Formative Practice 1.7 1. Be honest and precise in recording and approving data and have a positive attitude 2. Be responsible towards health, safety and environment Summative Practice 1 1. Corrosive material 2. V → R → P →T → Q → W → U→ S 3. 0.1 kg 4. (a) Lever balance (b) Vernier calipers 6. 34 squares x 1 cm2 = 34 cm2. Area of both wings = 34 cm2 Chapter 2 Formative Practice 2.1 1. (a) platelets, blood circulatory (b) Lungs, kidneys and skin 2. Palisade cell - Absorbs sunlight for photosynthesis Epidermis cell - Reduces water loss Root hair cell - Absorbs water from soil Guard cell - Controls the opening and closing of stoma 3. Cell wall Formative Practice 2.2 1. Photosynthesis. To produce glucose and oxygen 2. Glucose, cell respiration Summative Practice 2 1. P = cytoplasm, Q = nucleus, R = mitochondria 2. Kidney, lung 3. (a) ovum (b) red blood cell (c) nerve cell 4. Plant cells have cell wall, chloroplast, vacuole and fixed shape. Chapter 3 Formative Practice 3.1 1. Homeostasis is the process of maintenance of the internal environment in an organism. 2. Temperature regulation and water regulation Summative Practice 3 1. Through transpiration that helps plants to absorb and transport water and minerals from the soil to all parts of the plant to replace water loss to the surroundings from the leaves. Water lost to the
surroundings through evaporation is able to help the plant cool itself down during hot weather. 2. Blood vessels constrict to reduce heat released to the surroundings. Hair stands erect to trap heat from being lost to the surroundings. Less sweating to reduce heat loss through evaporation. Skeletal muscles contract and relax actively causing our body to shiver and increase the body temperature. At the same time, certain hormones are secreted to increase the body’s metabolism. 3. Blood vessels dilate to enable more blood to flow near the surface of the skin to release more heat to the surroundings. 4. Enables enzymes to function optimally at 37ºC to regulate all chemical reactions inside living cells. Chapter 4 Formative Practice 4.1 1. Sexual Reproduction
• Involves reproductive cells • Occurs in humans, animals (high level) and flowering plants
• Involves two parents
Asexual Reproduction • Does not involve reproductive cells • Occurs in simple organisms (Amoeba, Paramecium, Hydra) and plants (onion, ginger, potato) • Involves one parent
2. (a) Onion; bulb
(b) Yam; stem (c) Ginger; stem (d) Lallang; stem (e) Potato; stem (f) Bryophyllum; leaf. 3. Reproduction is important to ensure the survival of species. Formative Practice 4.2 1. To produce offsprings. 2. Function of urethra: To discharge sperms (and urine) from the body Penis: Transfers sperms into the vagina during copulation Scrotum: Holds and protects the testes 3. Function of Fallopian tube: The place where fertilisation between sperm and ovum occurs Function of vagina: Receives sperms and it is the birth channel through which a baby is born Function of uterus: Place where the embryo develops and grows 4. The early stage in which the reproductive system becomes mature and produces reproductive cells. Formative Practice 4.3
1. (i) Menstruation phase (Day 1-5)
The uterine lining breaks down as menstruation begins and is discharged together with blood, unfertilised ovum and mucus.
(ii) Repair phase (Day 6-11) Uterine lining starts to rebuild and thickens. Blood vessels in uterine lining are formed and ready to receive the implantation of fertilised ovum. (iii) Ovulation phase (Day 12-17) An ovum is released from the ovary on the 14th day of the menstrual cycle (ovulation). The uterine lining continues to thicken. Fertilisation is likely to occur if sperms are present. (iv) Premenstrual phase (Day 18-28) The uterine lining continues to thicken and becomes richly supplied with blood vessels. Implantation of an embryo is ready if fertilisation occurs. The menstrual cycle will repeat if fertilisation does not occur. 2. A woman begins to get menstruation between 10-12 years old, for 5-7 days. 3. Ovulation is the process of matured ovum being released from the ovary and it occurs in the ovary. Formative Practice 4.4 1. No. 2. After fertilisation, zygote divides itself into a ball of cells called embryo. Embryo that is implanted on the uterine lining continues to develop into foetus and eventually becomes a baby. 3. Zygote → Embryo → Foetus → Baby 4. Function of amnion: A sac-like membrane which contains fluid Function of placenta: Place where exchange of oxygen and carbon dioxide, supply of nutrients and removal of waste materials through the mother’s blood and the foetus occur. Function of umbilical cord: Tube which connects the foetus to the placenta. Formative Practice 4.5 1. A pregnant woman needs more nutrients because the baby inside her uterus needs nutrients to grow healthily. 2. Baby absorbs calcium from the mother for the growth of its own teeth and bones. Formative Practice 4.6 1. Factors of male sterility: (i) Low quality of sperm (ii) Low sperm count (iii) Testes cannot produce sperm (iv) Impotent Factors of female sterility: (i) Ovaries cannot produce ovum (ii) Blockage in the Fallopian tubes (iii) Abnormal uterus (iv) Tumour in the uterus 2. (a) Hormone injection and surgery (b) Treatment using IVF method 3. (a) Vasectomy: Sperm ducts are cut and the two ends are then tied to prevent the sperms from being transported to the urethra. Answers
279
(b) Ligation: Both Fallopian tubes are cut and the two ends are then tied to prevent the ovum from meeting the sperms. 4. Test tube baby is a baby that is formed using the IVF method. The sperm and ovum are fertilised in a glass dish. Then, the fertilised embryo is put inside the uterus to develop.
Formative Practice 4.7 1. Attracts insects for pollination 2. Sepal: usually green in colour and protects flower during the bud stage. Petal: usually colourful to attract insects and animals. 4. (a) Function of stigma: receives pollen grains (male gametes) (b) Function of style: connects stigma to ovary (c) Function of anther: produces male gametes 5.
Wind • Light pollen grains • White and dull • Number of pollen grains is high
Insects • Sticky pollen grains • Bright coloured • Number of pollen grains is low
Summative Practice 4 1. (a) Amniotic fluid (b) Acts as a cushion to absorb concussion and prevents foetus from injuries. (c) Placenta. The foetus obtains food and oxygen from the placenta through the umbilical cord. (d) When foetus is completely formed, the body will rotate until the head is engaged to the cervix. The cervix expands to enable the baby’s head to go through the vagina. The uterine muscle wall contracts strongly, bursts the amnion and amniotic fluid is released. Strong contraction of the uterus pushes out the baby. Chapter 5 Formative Practice 5.1 1. Matter: Book, pencil, pen, glass and beaker (Any other answers are accepted) 2. Has mass and occupies space 3. Yes, because all living things have mass and occupy space 5. Physical properties Chemical Properties • Depend on the type of material it is made of.
• Depend on the reaction that occurs upon the substances.
Formative Practice 5.2 1. (a) (i) Bubble: Gas (ii) Water: Liquid (iii) Water weed: Solid (iv) Aquarium: Solid
280
Answers
(v) Fish: Solid (b) Solid: book, glass, cloth Liquid: oil, petrol, milk Gas: air, carbon dioxide and oxygen (Any answers are accepted) (c) State of matter
Arrangement
Solid
Close and packed
Liquid
Close but not in orderly manner Far apart from each other
Gas
Movement Vibrate and rotate at its position Move freely, glide and collide with each other Move randomly, freely and collide with each other very fast
2. Food smell spreads through diffusion of the smell particles into the air particles. 3. Particles in matter always move and collide with one another 4. Temperature does not change because heat is used to overcome the force of attraction between the particles and thus, no change in temperature. Summative Practice 5 1. (a) Coffee: liquid Stones: solid Air in the balloon: gas (b) Coffee and stones (c) The particles only vibrate in the stone and rotate at its position while air particles move randomly and collide with one another with high kinetic energy. 4. (a) The air particles are compressed nearer to each other. (b) Tan’s action is correct as it can cause the tyre to expand during hot weather and explode it. (c) The air inside the tyre contracts when it is cold because heat is released and this will cause the particles of the gas to move nearer to one another and flatten the tyre. Chapter 6 Formative Practice 6.1 1. Proton, electron and neutron 2. The number of electrons in an atom is equal to the number of protons. Thus, an atom is neutral. 3. An element is made of only one type of atom while a compound consists of two or more elements that are combined chemically. 4. An atom is the smallest particle of an element while a molecule is a combination of two or more atoms. 5. Elements are arranged according to the proton number.
6.
Metal
Non-metal
Magnesium
Carbon
Aluminium
Iodine
Copper
Chlorine
Gold
Neon
Iron
Argon
Mercury
-
Formative Practice 6.2 1. Mixture is a substance that consists of two or more elements or compounds combined physically. 2. Type of mixture Paper clips and glass fragments Water and ethanol Three types of water soluble ink Soil and water Oil and water Coffee powder and water
Separation method Filtration Distillation Chromatography Using magnet Sedimentation Floatation
Formative Practice 6.3 1. Compound is a substance consisting of two or more elements combined chemically 2. Sugar, salt, water, marble, building blocks 3. Electrolysis 4. Mixture Characteristics Compound No No No heat changes Physical method Same
Formation of new substance Chemical bond Heat changes during formation Separation method Properties compared to its original properties
Yes Yes Yes Chemical method Different
Summative Practice 6 1. (a) (a), (b), (e), (f), (g), (h), (m), (n), (p) (b) (c), (i), (j), (o) (c) (d), (k), (l) Chapter 7 Formative Practice 7.1 1. Nitrogen 78%, oxygen 21%, carbon dioxide 0.03%, inert gases and others 0.97% 3. Carbon dioxide is used by plants for photosynthesis. 4. Greenhouse effect and global warming
Formative Practice 7.2 1. Combustion is the reaction when a substance is heated with oxygen and releases heat and light energy 2. The presence of oxygen, heat and fuel 3. Fire blanket is a special blanket made of fire-resistant substances. This blanket covers the fire and prevents oxygen from seeping below the blanket which will eventually extinguish the fire. 4. (a) Always be aware of electrical appliances used. (b) keep matches and lighters in a safe place. (c) Keep away flammable substances from fire. (d) Do not throw cigarette butts when they are still burning. (e) Do not plug in too many appliances to a single electrical source. (f) Install fire alarm at home. 5. Potassium and sodium metals are flammable when exposed to the air Formative Practice 7.3 1. Smoke and dust 3. (a) Humans can stay healthy. (b) Reduce the cost of repairing damaged buildings by acid rain. (c) Earth’s climate will be better. 4. Rubbish can cause the increase of microorganisms in the air. 6. (a) ✓ (b) ✓ (c) (d) ✓ (e) Summative Practice 7 1. (a) P: Nitrogen Q: Oxygen R: Inert gases S: Carbon dioxide (b) (i) Needed to produce nitric acid and ammonia (ii) Helps in animal and plant growth (c) The temperature increases as gas S traps heat. (d) (i) Air components can be separated physically. (ii) Each gas still shows its original properties when separated. 2. (a) Carbon dioxide (b) Argon (c) Atmosphere (d) Oxygen 3. (a) Green plants are the only living things that can absorb and reduce carbon dioxide in the atmosphere through photosynthesis. When a lot of trees are cut down, carbon Answers
281
dioxide which is released through respiration, combustion and decomposition will increase the percentage of carbon dioxide in the atmosphere. (b) Fossil fuel burning/ burning of forests (c) Greenhouse effect and global warming 4. (a) Combustion is the reaction when a substance reacts with oxygen chemically and produces heat and light energy. (b) Heat, oxygen and fuel (c) (i) Ensure the electrical wiring is according to the right specification (ii) Use dry powder fire extinguisher (d) (i) Install smoke detectors and fire alarm at home (ii) Do not plug too many appliances on a single electrical source. (iii) Always be aware of the electrical appliances used. 5. (a) Haze (b) Causes breathing difficulties and cough
makes the image of the bottom of the swimming pool to look shallower compared to its real depth. 2. A: Less dense B: More dense
C: More dense
D: Less dense
Formative Practice 8.5 1. Red, orange, yellow, green, blue, indigo, violet 2. Red light is refracted the least because it is the fastest. Meanwhile, violet light is refracted the most because it is the slowest. Formative Practice 8.6 1. Scattering of light occurs because light rays are blocked and reflected to all directions by the clouds or particles in the air. 2. more, less Formative Practice 8.7 1. A = Magenta, B= Cyan, C= Yellow, D = White 2. (a) red
Chapter 8
(b) green
Formative Practice 8.1
(c) magenta
1. Convex mirror, the man looks slim
Summative Practice 8
2. To reflect light so that the image can be formed in the eyes
1. A real image can be formed on a screen while a virtual image cannot be formed on a screen.
3. To make the small space look spacious and comfortable. The mirrors are security measures too as a person could see all around him.
2. B
Formative Practice 8.2
Formative Practice 9.1
2.
Formative Practice 8.3 1. According to the law of reflection, angle of incidence, i, is equal to angle of reflection, r. Normal
i
Reflected ray
r
Plane mirror
2. Upright, same size with the object, virtual, same, (also laterally inverted) Formative Practice 8.4 1. When light rays from the bottom of the swimming pool leave the water, they are refracted. This
282
Answers
4. (a) Magenta, (b) Yellow, (c) Cyan , (d) White Chapter 9
1. afternoon, above
Incident ray
3. X and Z
1. hydrosphere, biosphere, geosphere, and atmosphere. Formative Practice 9.2 1. Igneous rocks are formed when magma from volcano eruptions cools when it rises to the surface. Sedimentary rocks are formed from various rock fragmentation processes such as weathering and erosion. It is then carried by the river to the sea and deposited there. Metamorphic rocks are the rocks formed when pressure and heat acts on igneous and sedimentary rocks. 2. Igneous rocks are formed from cooled magma. Magma has a high temperature and no living things can live in it. Therefore, there are no fossils found in igneous rocks. 3. Metamorphic rocks are harder than other rocks because they are formed from high pressure and temperature.
Formative Practice 9.3 1. Exogenic process – a process that occurs on Earth’s surface Endogenic process – a process that is caused from within the Earth 2. Water, wind and waves 3. Earth’s crust is divided into several plates. These plates always move due to collision and divergence that produce various landforms and continental drifts. 4. Mantle convection process happens when the high temperature inside the mantle and Earth’s core produce convection flow in the asthenosphere that is able to move Earth’s crust. Formative Practice 9.4 1. Landslide, tsunami, earthquake 2. Destruction of properties, loss of life, diseases, famine. 3. Seismograph to detect earthquake, radar to detect tsunami. Formative Practice 9.5
Formative Practice 9.6 1. Deforestation can cause lack of oxygen production and carbon dioxide content in the air to increase. This will cause global warming as carbon dioxide is a greenhouse gas that can trap the heat from the Sun. Lack of oxygen content will also reduce oxygen for respiration. Deforestation can also cause soil erosion. 2. Recycle, use mineral materials wisely. Summative Practice 9 1. P: Crust , Q: Mantle, R: Outer core, S: Inner core 2. Troposphere 3. (a) S (b) Birds and insects 4. Mineral composition of original rocks, pressure and temperature, tectonic process and hot chemical fluid Full answers for teacher, please scan QR code.
1. 500 million years ago 2. Insects 3. 1000 million years ago
Answers
283
Atom
The smallest particle of an element that can take part in a chemical reaction
Accuracy
The closest degree of a measured value to an actual value
Area
The size of a surface
Air pollution
The situation involving the introduction of any chemicals, particulate matter, or biological materials that can cause harm, discomfort to humans or other living organisms and damage to the environment when released into the atmosphere
Binary fission
The division of a parent cell into two daughter cells
Budding
The process of forming buds in an organism
Consistency
The ability to give the same reading when the measurement is repeated
Carbon cycle
A cycle that maintains the carbon dioxide content in the air by taking carbon dioxide from the air and returns it back into the air continuously
Cell
The basic unit of living things
Cell respiration
Process of oxidising glucose in the cells of organisms to produce energy.
Combustion
Reaction that occurs when a substance reacts with oxygen chemically and releases heat energy
Cross-pollination
Transfer of pollen grains from anther to stigma involving two parent plants of the same species
Compound
A substance consisting two or more elements joined chemically
Density
The mass per unit volume
Diffusion
Process in which particles of a matter move from an area of high concentration to an area of low concentration
Electrolysis
The decomposition of a compound to its elements when an electric current flows through it
Erosion
A diminution process on the earth’s surface due to the action of moving agents such as flowing water, wind and waves
284
Bab 8 Glossary
External fertilisation
Process where the nucleus of a male gamete fuses with the female gamete outside the body of the female
Exogenic process
The process that occurs on the Earth’s surface
Endogenic process
The process that is caused by forces from within the Earth
Element
A substance that consists of one type of particle only
Fire extinguisher
Fire protection device used to extinguish fire or control small fires, often used in emergency situations
Homeostasis
The regulation of internal environment in an organism, such as temperature level, water, pH, blood pressure and so on, so that it remains at a balanced and stable condition
Igneous rock
Rock formed from the cooling and freezing process of magma or lava that flows out from the mantle
Infertility
Inability to produce offspring/ conceive baby
Internal fertilisation
Process where the nucleus of a male gamete fuses with the nucleus of a female gamete in the body of the female
Light subtraction
Coloured light which is the same as the colour of an opaque object will be reflected to our eyes while the other colours are absorbed
Light scattering
Rays of light reflected in all directions by clouds or particles in the air
Metamorphic rock
Rock formed when igneous or sedimentary rocks are exposed to very high pressure and temperature
Mixture
A substance consisting of two or more elements or compounds combined physically
Menstruation
The breakdown of the lining of the uterine wall and discharge of blood through the vagina
Matter
Any substance that has mass and occupies space
Mass
The quantity of matter contained in an object
Menstrual cycle
A series of changes that occurs in the lining of the uterine wall and ovaries
Multicellular organism
An organism that consist of more than one cell
Oxygen cycle
A cycle that involves taking oxygen from the air and returning it to the air continuously
Organ
A group of different tissues joined together to perform a specific function Glossary Bab 8
285
Puberty
The period during which adolescents reach sexual maturity and become capable of reproduction
Physical quantities
The physical properties that can be calculated and measured
Parallax error
The error due to the position of the eyes which are not perpendicular to the scale reading when taking measurements
Primary colours
Basic colours that cannot be produced by mixing colours
Real image
The image formed on a screen
Reproduction
Process to produce new individuals by living organisms
Refraction of light
The change of light direction or the bending of light when it passes through two mediums of different densities
Regenerative
The ability of specific fragment of organisms to grow and develop into a new complete individual
Respiration
Gas exchange that occurs between the organism and its environment
Science
A discipline that involves the observation and the systematic experiment towards the nature of a phenomenon
Scientific method
Systematic method used to solve a problem in science
Sedimentary rock
Rock formed by compression of sedimented materials carried by rivers, glaciers and wind
Sensitivity
The ability to detect small changes of the quantity to be measured
Spore formation
Process of producing spores in the sporangium
Systematic errors
The error caused by measuring instruments that are less accurate or zero error that occurs in the measuring instrument
System
A group of organs joined together to perform a specific function
Stoma
Tiny pore on a leaf that controls the entry of air into the leaf
Secondary colours
Colours produced when two primary colours are mixed together
Tissue
A group of cells joined together to perform a specific function
Unicellular organism
An organism that consists of only one cell
Virtual image
An image that cannot be formed on a screen
Vegetative reproduction
Production of new plants from vegetative parts of a parent plant and does not the flower
Weathering
A process of fragmentation and decomposition or decay of rocks due to changes in temperature, rain, frost action and microorganisms
286
Bab 8 Glossary
Clarke, J., Levesley, M., Pimbert, M., Johnson, P., Baggley, S., & Gray, S. (2002). Exploring Science 7, Edinburgh Gate: Pearson Longman. Chen, L. K., Clare, E., Sadler, J., Tan, Y. T. (2007). G.C.E.’O’ Level, Chemistry Matters, Singapore: Marshall Cavendish Education. Garton, A., & Williamson, K. (2005). Science for Life 7, Australia: MacMillan Education Australia Pty Ltd. Fellowes-Freeman, D., Sang, D., & Jones, M. (2012). Cambridge Checkpoint Science Coursebook 7, United Kingdom: Cambridge University Press. Fellowes-Freeman, D., Sang, D., & Jones, M. (2012). Cambridge Checkpoint Science Coursebook 8, United Kingdom: Cambridge University Press. Goh, H. C., Gui, E. H., & Tan, K.S. (2014). Science Around Us, Module 1 Gadgets Work Wonders (I), Singapore: Star Publishing Pte Ltd. Goh, H. C., Gui, E. H., & Tan, K.S. (2014). Science Around Us, Module 2 Gadgets Work Wonders (I), Singapore: Star Publishing Pte Ltd. Goh, H. C., Gui, E. H., & Tan, K.S. (2014). Science Around Us, Module 3 Gadgets Work Wonders (I), Singapore: Star Publishing Pte Ltd. Ho, P.L. (2009). International Lower Secondary Science 1, Singapore: Marshall Cavendish Education. Ho, P.L. (2009). International Lower Secondary Science 2, Singapore: Marshall Cavendish Education. Johnson, P. (2006). 21st Century Science, Science GCSE Foundation, Edinburgh Gate: Peason Longman. Lee, C., Lam, E., Fong, J., Lam, P. K., & Loo, P.L. (2014). Lower Secondary Science: Volume A : Matters (2nd ed.). Singapore: Marshall Cavendish Education. Lee, C., Lam, E., Fong, J., Lam, P. K., & Loo, P.L. (2014). Lower Secondary Science: Volume B : Matters (2nd ed.). Singapore: Marshall Cavendish Education. Lofts, G., & Evergreen, M. J. (2000). Science Quest 1, Australia: John Wiley & Sons Australia, Ltd. Segaran, P. R., Yuen, K. S. (2002). Textbook for Secondary 2, Science Vision, New York: Oxford University Press. Yip, P. (2003). Biology for Tomorrow, Hong Kong: Manhattan Press (H.K.), Ltd.
Reference
287
Air pollution 208 Amniotic fluid 109, 110 Anther 120, 121, 122, 123 Asexual reproduction 91, 95 Atmosphere 256, 257, 259 Atom 164, 165 Biosphere 256 Bisexual flower 121 Boiling 151, 153 Carbon cycle 200 Cell 46, 47 Cervix 99, 109 Chloroplast 50, 52 Condensation 152, 153 Combustion 204 Compound 166, 167 Cross-pollination 122 Cytoplasm 50, 51, 52 Dicotyledonous 127 Ductility, 169, 172 Diffusion 148, 149 Distillation 177, 179 Electrical conductivity 169, 173 Electron 164, 165 Element 166 Embryo 99, 105, 109 Endogenic process 264 Exogenic process 263 Evaporation 153 Fertilisation 93, 105, 107, 108 Filtration 177, 178 Floatation 177, 181 Foetus 109, 111, 113 Fossils 262, 268, 269 Freezing 151, 152, 156 Gamete 92, 93, 98, 102 Geohazards 265, 266 Geological time scale 268
288
Index
Geosphere 256 Heat conductivity 169, 173 Homeostasis 72, 73, 78, 79, 80, 83 Hydrosphere 256 Hydrothermal 272 Hypothesis 33, 34, 35 Igneous rocks 261, 262 Implant 117 Inert gases 196, 199 Infertility 107, 115 In vitro fertilisation 116 Liquid 141, 146, 147, 150 Malleability 169, 172 Matter 138, 140, 141 Melting 152, 153 Menstrual cycle 104 Metal 167, 169, 170 Metamorphic rocks 261, 262 Mixture 176 Micropyle 127 Monocotyledonous 127 Multicellular 53, 54, 55 Neutron 165 Nitrogen 196, 199 Nucleus 50, 51, 52 Organ 55, 56, 57 Oxygen cycle 201 Oxygen 196, 197, 199 Ovary 92, 99, 101, 105, 120 Ovulation 105 Ovules 120, 121 Ovum 92, 93 Periodic Table 167, 168 Penis 98 Petal 120, 121 Pistil 120 Plumule 127, 128
Placenta 110 Puberty 100, 101, 102 Refraction 233, 234, 235 Reflection 223, 226, 227, 230, 231, 232 Radicle 127, 128 Random error 20, 26 Sedimentary rocks 261, 262 Sexual reproduction 90, 91, 92 Self-pollination 122 Shiny surfaces 169, 172 S.I. unit 15, 17, 18, 19, 20, 27 Sperm duct 98, 116 Sepals 120, 121 Seminal vesicle 98 Scattering of light 239, 240, 241 Solubility 143 Solid 146, 147, 149 Sperm 92, 102, 103 Sublimation 151, 152, 153 Stoma 80, 81 Stamen 121 Style 120, 121 Stigma 120, 121 Surface water 270 Tensile strength 169 Testa 127 Testis 92, 98, 101 Tissue 55, 56 Underground water 270 Unicellular 53 Unisexual flower 121 Urethra 98 Uterus 99, 104, 105 Vagina 98, 99 Virtual 222, 231 Zygote 108
Dengan ini SAYA BERJANJI akan menjaga buku ini dengan baik dan bertanggungjawab atas kehilangannya serta mengembalikannya kepada pihak sekolah pada tarikh yang ditetapkan
Skim Pinjaman Buku Teks Sekolah ______________________________ Tahun
Tingkatan
Nama Penerima
Tarikh Terima
Nombor Perolehan: ____________________________ Tarikh Penerimaan: ____________________________
BUKU INI TIDAK BOLEH DIJUAL