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HMH Science Dimensions Earth & Space Science Sample Flipbook PDF
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UNIT 3
Natural Resources Lesson 1: Designing Solutions to Resource Problems . . . . . . . . . . 112 Lesson 2: Rock and Mineral Resources . . . . . . . . . . . . . . . . . . 128 Lesson 3: Energy Resources . . 146 Thing Explainer . . . . . . . . . . . . . 166 Unit Connections. . . . . . . . . . . . 170 Unit Review . . . . . . . . . . . . . . . . . 171
Rock, mineral, and energy resources affect almost every aspect of our daily lives.
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Image Credits: ©exzozis/Fotolia
Unit Performance Task . . . . . . . 173
FIGURE 1: Landfill and an open-pit mine
a Materials that are not recycled can end
up in landfills like this one.
b Mineral resources such as copper are
mined from Earth’s crust.
The availability of natural resources is essential for modern life. However, resource exploration, mining and drilling, processing, and disposal can all have a negative impact on Earth’s living and non-living systems. Predict What are some ways in which the use of rock, mineral, and energy resources
affect other natural resources on Earth?
DRIVING QUESTIONS As you move through the unit, gather evidence to help you answer the following questions. In your Evidence Notebook, record what you already know about these topics and any questions you have about them. 1. How has human society been influenced by the availability of rock, mineral, and energy resources? 2. What is the impact of developing and using rock, mineral, and energy resources on Earth’s living and non-living systems?
Image Credits: (l) ©Alamy; (r) ©Gary Whitton/Fotolia
3. How can the engineering design process be used to solve environmental, social, and economic problems related to the availability, development, and use of rock, mineral, and energy resources?
UNIT PROJECT
Recycling Resources
Go online to download the Unit Project Worksheet to help plan your project.
What materials can be recycled where you live? How are these materials recycled? Research the recycling system in your area. Evaluate the system in terms of how well it serves your community and how well it protects the environment. Write a proposal to the local government for improving the system. Your proposal should describe the existing system, describe one or more changes you think should be made, and provide reasoning for these changes.
Unit 3 Unit Closer
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3.1
Designing Solutions to Resource Problems
CAN YOU EXPLAIN IT? FIGURE 1: Plastic and paper bags each have disadvantages.
a
Gather Evidence
As you explore the engineering design process, use it to help you look at the paper-orplastic choice in new ways and to make informed choices.
Plastic bags don’t degrade easily.
b
Paper bags can break when wet.
Individuals, stores, and communities have often had to choose between paper bags and plastic bags. There are reasons for each choice. Plastic bags are made from materials extracted from underground, such as oil. Paper bags are made from wood pulp from trees, which can be regrown. Paper may seem to be a better choice for the environment. However, people think about many factors when choosing between paper and plastic bags. Plastic bags require less energy to produce than paper bags. They are lighter in weight and cost less to ship. Both types of bags can be recycled, but if both are thrown out, then plastic bags take less space in a landfill. However, plastic bags take longer to decompose. People disagree about which bag is more harmful to the environment. The choice involves more than environmental issues. People have different opinions about which bags are easier or better to use. Plastic bags are not harmed by water but may tear. Paper bags may hold more items—at least, when dry. Explain Which type of bag—paper or plastic—do you think should be used in stores
in your community? Explain your reasoning.
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Image Credits: (t) ©moonrise/Fotolia; (bl) ©Jeffrey Phelps/Aurora/Getty Images; (br) ©Diane Collins and Jordan Hollender/The Image Bank/Getty Images
Aluminum is much more efficient to recycle than to extract from raw materials.
EXPLORATION 1
Managing Natural Resources Many of the objects around you are made of materials that came from the geosphere. Other materials come from the biosphere, hydrosphere, atmosphere, or more than one sphere. Energy comes from Earth’s spheres and from sunlight. People—including you—make choices every day that affect the future of these natural resources.
Human Uses of Resources
Collaborate With a
partner, use Earth’s spheres as a way to try to classify the main resource(s) involved in food, radio communication, tap water, farmland, and nuclear power.
Energy, materials, and products made from materials are resources, but there are also other types of resources. Space on Earth’s surface and in the air above it can be resources, such as rivers used for transportation. For example, the Panama Canal is a resource because it shortens travel and transportation between the Atlantic and Pacific Oceans. Biodiversity, or the variety of organisms, is an important resource. Part of the value of biodiversity comes from the complex ways that organisms interact with other spheres. For example, trees in rainforests remove a lot of carbon dioxide from the air.
Image Credits: (t) ©Ammit/Fotolia; (b) ©aldomurillo/ E+/Getty Images
FIGURE 2: Rainforests have a wide range of organisms—they are very rich in biodiversity.
Predict Why else might people think of biodiversity as an important resource?
Many human activities include the use of natural resources, even when the activity doesn’t seem to be about resources. For example, laws, ownership of land, and discussions between countries often involve natural resources. People manage resources to make sure that the resources are available now and in the future. You may already know some actions, such as recycling, that people take to manage resources. FIGURE 3: People ask some common questions when solving problems. Some of the questions are tied to resources.
our goal? e achieve How can w ? Will it work st? What will it co How long will it take? What else will this solution affect? Who else will be affected ? Should they help make decisions? How safe will it be ? How well w ill we like th e result?
Lesson 1 Designing Solutions to Resource Problems
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Gather Evidence
Record and compare a few different ways that people classify resources.
Types of Resources Resources have different properties. Some resources are nonrenewable—a limited amount of the resource exists, or it is used more quickly than it can form. Other resources are renewable—the resource can be replaced at the rate it is used. For example, sunlight is renewable, while metals from Earth’s crust are nonrenewable. However, a resource that is renewable now may become nonrenewable if people use it faster than it can be replenished naturally. People may evaluate whether the use can continue—whether it is sustainable—or whether the resource will be used up. Other properties include whether a resource is found everywhere or only in certain areas and whether it is very limited, such as gold, or plentiful, such as sunlight. Some resources are difficult to transport or store. Many human activities depend on energy resources. Preparing and using materials usually requires a fuel or other source of energy. Fossil fuels, including coal, oil, and natural gas, formed from organisms that lived long ago. They are nonrenewable and are found only in some places. About 80% of the energy resources used in the United States in 2015 came from fossil fuels. When fossil fuels are burned, they produce pollution and affect human health. In the regions where the fossil fuels are collected, the environment and lives of people can be affected.
Analyzing a Resource As you saw with the choice of paper or plastic bags, human activities can have many different effects. The effects of an activity occur from the time any raw materials are gathered until the activity ends and any remaining material or waste is in its final storage. This full view is called a life cycle. You can use a model of a life cycle, such as that shown in Figure 4, to think through all of the effects of an activity or to compare choices. A life-cycle analysis can be a way to compare the total use of fossil fuels for paper and plastic bags. The analysis can help you make informed choices. Evaluate Would your choice of paper or plastic bags change if you compared their life cycles? Explain.
FIGURE 4: Trace the entire life cycle of a product from its origin to when it becomes waste.
material extraction
raw material, fuel/energy
recycling, recovery
landfill, burning, wastewater
transport, processing, production
refurbishing, reuse
dismantling, waste management
storage, distribution
consumption/use, maintenance
Communities and businesses use this type of analysis to help manage natural resources. They may use experts in engineering, science, and business to try to achieve a balance between different needs and wants. These experts may examine a range of factors—physical, economic, legal, political, social, and ethical—to help keep projects within budgets, ensure sustainable use of resources, and protect the environment. 114
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Engineering FIGURE 5: Harmful chemicals are used
Costs of Making Jeans
to make jeans look worn. Engineering design involves making choices, which can reflect what a community values. A design with a lower price may have hidden environmental costs. A life-cycle analysis is a tool from engineering design that can reveal these costs. For example, a pair of jeans requires about 3,700 liters of water. Some of this water is used to grow cotton, which is the raw material for jeans. Some water is used whenever the owner washes the jeans. Carbon dioxide is released into the environment in the making, using, and disposing of a pair of jeans. Chemicals from denim processing pollute water and land. Analyze What might you do to reduce the negative effects on the
environment of buying, using, and disposing of jeans?
The Engineering Design Process Engineers look at a need or a want as a problem to be solved. They design ways to achieve that goal. The ways that they identify and solve problems are jointly called the engineering design process. A simple model for this process has three phases: defining the problem, designing solutions that can work, and optimizing, or trying to use the best solution. The process can start with any of the phases. Engineers usually go back and forth between the phases many times as they learn about the problem, try possible solutions, and refine a solution.
Collaborate With a partner, list some pros and cons of using paper and plastic bags. Then, discuss how subjectivity came into the process of making the list.
FIGURE 6: A simple model of the engineering design process
Image Credits: ©Don Bartletti/Los Angeles Times/Getty Images
define Identify the goal (problem) and conditions for success. Start here with a need or want.
Design and test possible solutions. Start here when trying something new.
develop
optimize
Compare, choose, and improve solutions. Start here to improve something.
Analyze Think about some of the choices you make. Identify one choice that involves
the use of natural resources. How might the tools of engineering help you to make an informed choice? Lesson 1 Designing Solutions to Resource Problems
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EXPLORATION 2
Define a Problem The engineering design process very often starts with a situation that somebody wants to change. Defining a problem involves stating the want or need clearly and thinking about the characteristics of a successful solution.
Defining a Problem Analyze Paper bags and plastic bags are two possible solutions to a problem. What problem—what need or want—is being addressed?
A clear definition is a good way to start to solve a problem. You might visit other stages of the engineering design process briefly as you define a problem. For example, thinking about possible solutions may help you define a need or want. Sometimes, you will start a design process with one of the other stages, such as when you recognize a solution that would be useful. However, if you run into difficulties, a clear definition can be helpful. A definition can also help you determine the priority, or relative importance, of related goals. A definition can help you set clear goals and avoid getting distracted by a related problem. People may disagree about priorities. When a need or want involves several people, defining the problem can help the group work together to meet a shared goal. FIGURE 7: You can make or adjust a definition as needed when developing and optimizing solutions.
define Change a situation Start with a definition when you know the need or want.
develop
optimize Gather Evidence
To make buildings more accessible, engineers consult people with disabilities. How might consultation help define the problem?
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Fix a problem If you have difficulty making a solution work, pause to define the problem.
Improve a solution State or review the goals to help you achieve the best solution
Engineers add detail to the definition of a problem. They list properties of a possible solution: the criteria and constraints. Criteria and constraints are usually grouped together, but sometimes looking at them separately can be useful. A constraint is a limitation or restriction on the solution. A proposed solution fails if it does not stay within the constraints. Cost and time are often constraints, because a proposed solution doesn’t solve the problem if you can’t afford it or if it occurs too late.
Criteria (singular: criterion) are the required or desired properties of a solution. Some criteria are more important—higher priority—than others. One way to spell out importance is to determine which criteria are required and which are only desired. In the choice of paper or plastic bags, a required property would be the ability to hold a customer’s purchased items. A desired property might be that the bag be attractive. You can also set priorities by ranking the criteria from most to least important. A third approach is to rate each criterion by giving it a relative value, sometimes called a weight. Later, when you evaluate possible solutions, weights can make the job easier.
Gather Evidence
Record an example of a time you had to set priorities to solve a problem. Were you defining the problem?
Example: New Light Figure 8 shows a dark landing at the top of the first set of stairs in an apartment building. The dark landing is a safety hazard for residents and their visitors. Some people have tripped and fallen when walking from the first set of stairs to the second. The building manager wants to improve this situation. One resident has asked for a table and a lamp on the landing. Another resident prefers a ceiling light, because a table would make the landing too narrow. A third resident has suggested a new window in one wall to make the landing lighter and more attractive. It may be best to define the problem before choosing a solution. The manager has determined that any solution must cost no more than $300, including the cost of maintenance and energy for the rest of the year. FIGURE 8: The dark landing at the top of these stairs is a safety hazard. The top few stairs
define this problem?
Image Credits: ©theprint/iStock/Getty Images Plus/Getty Images
of this set are difficult to see. The bottom few stairs of the second set, beyond the panel on the right, are also dark.
Explain How would you
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Hands-On Activity MATERIALS • pencil • paper or sticky notes • spreadsheet application (optional)
New Light: Criteria and Constraints 1. Make an initial table, perhaps by using a computer spreadsheet application. Use these column headers: Criterion or Constraint, Weight. Plan to adjust your table and to add more columns later (for possible solutions). 2. For the new-light problem, list each criterion or constraint (each item) in a separate row or on a separate sticky note. Mark the constraints in some way, such as by underlining them. 3. Compare the importance of the items. Judge the relative importance of the criteria. Assign each criterion a weight between zero and ten, such that the weights add up to ten. Constraints are limitations that must be met for a solution to be acceptable, so leave their weights blank. 4. Put the criteria in order of decreasing importance from the top of the column. Put the constraints below the criteria. Analyze
1. Which items involve natural resource issues? 2. Compare your table to that of a classmate. How do your judgements of the importance of items differ? 3. Did the comparison help you improve your table?
Comparing Science and Engineering Analyze List at least
two ways to measure or describe the growth of a plant. How would you decide which operational definition to use?
Science and engineering share many tools, such as models and math, but they have differences. An awareness of the differences can help you use what you know about science to develop skills in engineering design. The main focus of science is explaining phenomena. The main focus of engineering is solving problems. It often involves applying scientific knowledge. In science, variables are examined separately, or controlled, whenever possible. Controlling variables is also useful in engineering design, especially when testing ideas. However, a solution often involves a balance between many factors at the same time. A tradeoff is the reduction of one desirable characteristic in order to increase another, usually because the two characteristics can’t both be maximized. Tradeoffs are sometimes made when defining a problem, but they are more common in other stages. Exact, complete definitions are often a goal of science. Definitions in engineering may be more practical than exact. Engineers and scientists both use operational definitions, or descriptions of how to measure a concept or variable in a particular situation. Science emphasizes replicating or repeating tests in exactly the same way. Iterating, or repeating with small improvements or variations, is typical of engineering.
Collaborate With a partner, develop criteria and constraints to further define the problem of the choice of paper or plastic bags.
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EXPLORATION 3
Develop Solutions Designing and testing one or more solutions is often the second phase of engineering design. A successful solution meets at least the required criteria while staying within the constraints.
Developing Solutions
FIGURE 9: To develop a design, you may need to adjust a definition or to optimize some part of a design.
define
A design often begins with sketches of several ideas. A sketch provides a visual representation of, for example, components and processes. It can help you test an idea against the criteria and constraints. It can be a quick way of selecting or thinking through an idea. A sketch or other model can also uncover new limitations or other challenges, such as a space limitation or a part of a solution likely to be costly. FIGURE 10: A wide range of ideas may be possible—the first idea is not always best.
Some people have chosen to earn income through tourism, such as by building ziplines, rather than by cutting down rainforests for wood, grazing land, and farmland.
develop
optimize
Gather Evidence Make a note of a time you used brainstorming to generate possible ideas to develop into a solution.
Image Credits: ©piccaya/Fotolia
A common test of cost, for example, is to multiply the price of each component by the number needed or number of times it would need to be replaced. A spreadsheet application can be used to test many possibilities easily. Possible components might be tested until the total cost falls within the limitations. Iterations of testing and adjusting are often needed to develop a solution that meets criteria while staying within constraints. You will encounter many problems that are difficult to solve. However, you can usually divide a problem into parts and work on one part at a time. Team members may work on different parts at the same time. For example, one person might focus on how best to use a resource while another works out a good way to get the resource. You may need to go back and forth (iterate) so that the parts of the solution work well together. You may even need to go back to adjust the criteria and constraints.
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Patterns FIGURE 11: The solution to this
puzzle can help you think about other problems.
Adapting Existing Solutions Often, there is no need to develop a completely new solution to a problem because one already exists. The solution has already been tested and refined. It is typically much easier and more reliable to adapt such a solution than to start over. For example, the rope systems used to move large canvas sails on ships were adapted to move large pieces of canvas in theaters. In a classic puzzle, two people are challenged to escape. A rope with a loop on each end connects each person’s hands. The wrist loops are loose but must not be removed. The two ropes are linked in a way similar to the center of the puzzle in Figure 11. The solution to either puzzle can be adapted to solve the other puzzle.
Explore Online
Hands-On Lab Brightness and Color When
most light bulbs were incandescent, the amount of energy mostly determined the brightness, temperature, and color of the light. Go online for a lab to compare these properties in modern light bulbs.
Example: New Light The manager researches ways to make the stairway safer and finds several possibilities. One possible solution is a ceiling light. The manager tries to determine properties of such a fixture needed to solve the problem. The properties include the amount of light or brightness, which is measured in lumens. A lumen is about equal to the amount of light produced by a birthday candle. Energy usage per unit of time is measured in watts and forms part of the ongoing cost. The frequency and cost of replacing light bulbs must be considered, so the expected bulb lifetime is important. The light must shine on the nearest stairs but not shine in people’s eyes, so the manager determines the needed spread, or angular width, of the light beam. The manager finds that the color of the light is sometimes described as warm or cool, because people often describe red and yellow as warm colors and blue as a cool color. Sometimes color is given as an equivalent temperature in kelvin (K), called color temperature. In this measurement, a lower temperature such as 2700 K describes a yellowish light. Higher-color temperatures include more blue light. These temperatures are related to the filaments of incandescent light bulbs and other very hot materials.
Collaborate With a partner, sketch out one of the possible solutions to the choice of
paper or plastic bags. Include information for each criterion or constraint. 120
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Image Credits: (t) ©Andrzej Tokarski/Alamy; (b) ©ohsuriya/Fotolia
FIGURE 12: Color can be expressed as the temperature of a heated material that would produce that color.
EXPLORATION 4
Optimize a Solution The remaining stage of the engineering design process includes choosing or adjusting—optimizing—a solution to give the best possible results. The solution is evaluated against the criteria and constraints.
Optimizing a Solution A solution is acceptable only if it will meet the criteria and stay within the constraints. When several solutions are acceptable, the criteria can help determine which solution is optimal, or best. A tradeoff matrix is a chart to compare several solutions. When none of the solutions is perfect, some desirable qualities must be traded for others. Another way to analyze solutions is to look at costs, risks, and benefits. Benefits are the advantages of a solution. Costs include money paid and other disadvantages. Risks are costs that may or may not occur. The costs, risks, and benefits can be a way of looking at criteria and constraints of the problem, but often go beyond the problem itself. A solution can affect other systems, a local community, or even global issues. For example, many solutions affect the management of natural resources. Recall that a life-cycle analysis is one way to look at the total costs of a solution. Models can also be used to estimate risks. Published reviews can show how other people have evaluated possible solutions. Many tools can be used to evaluate solutions. The chosen solution is tested either in advance or when it is put into use. When a solution fails or isn’t good enough, engineers troubleshoot, or attempt to find the cause of the difficulty. A test may reveal flaws in a design or unintended consequences, such as an undesirable effect on something else. The design may need to be adjusted. FIGURE 12:
Image Credits: ©AwakenedEye/iStock/Getty Images Plus/Getty Images
A solution may introduce a new problem.
Analyze In a design of
safety belts in school buses, which of these would you trade for the others: cost, safety, or impact on the environment?
Predict Suppose you
change a light bulb to a new type, but it does not turn on. How would you find the problem? Discuss with a partner and come up with a good troubleshooting plan.
A solution can usually be improved. Sometimes, many iterations are needed to optimize a solution. For example, an improvement in safety or effectiveness may increase the price or cause additional harm to the environment. More iterations may help reduce these costs back to acceptable levels.
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FIGURE 13: Engineering
design involves iterating among the stages. define develop
optimize
To construct a tradeoff matrix, record a measure of how each solution meets each criterion and constraint. For example, you might add all of the costs to confirm that a design meets a spending limit or addresses a criterion of low price. You might use a scale of zero to five to rate how well a solution meets a criterion. Or, you might simply compare each solution to the current situation. For example, a store considering a change from paper bags might record +1 for durability if a new solution would break less often (be better) than paper bags, 0 if the new bags would break about as often as paper, and –1 if the new bags break more often. Subjective items can also be evaluated by rating. Ratings from different people may vary, so an average or an expert’s evaluation may help. You can combine the evaluations to give each solution an overall rating. A typical approach is to use the same rating scale for each criterion, multiply each by the weight assigned to the criterion, and add the results. Each solution then has a numerical score.
Example: New Light The manager has chosen to look separately at two different parts of a possible solution. One part is the choice of a fixture or lamp. Another part is the choice of bulb.
Data Analysis
comparison chart. Which light bulb seems best? Then use your list of criteria and constraints. What additional information would you need to optimize the solution?
Calculating Tradeoffs Add to your table of criteria and constraints for the new light problem by comparing partial solutions of each of the bulbs below. FIGURE 14:
Use information from this comparison chart in your tradeoff matrix.
The manager tries a quick test using a borrowed lamp with a standard incandescent bulb of 60 W. The test shows that 800 lumens is enough light. A check of prices shows that the lower-energy bulbs are more expensive. However, any of the four bulb types would be within the cost constraint. The manager chooses the best bulb, then considers the bulb and fixture together to optimize the solution.
Collaborate Find or prepare a tradeoff matrix for choosing plastic or paper bags. You may want to group some related factors, such as costs or environmental impacts. Compare your results with a partner and discuss how to optimize the solution. 122
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Image Credits: ©piai/Fotolia
Analyze Look at the
EXPLORATION 5
The Use of Iteration Iteration means to repeat a process, typically with a change. Expect to repeat different parts of the process when designing a solution.
Iterating through a Problem You’ve seen how people use the stages of the engineering design process repeatedly. With each pass through the stages, they learn more about the problem and about possible solutions. They apply what they learn to improve the work in other stages. If a test or design fails, they may study the failure to get ideas for an improvement or a different solution. When a problem is broken down, iterations may be used on the separate parts, then on several parts together, and then on the whole solution.
FIGURE 15: Lessons learned during other phases may cause you to redefine the problem.
redefine define develop
Hands-On Activity optimize
Practice Run Place a coin on the floor just below the edge of a table. Push a second coin off the edge of the table so that it lands as close as possible to the first coin. Then try again with a third coin. Explain Did the result of your first try help you do better on your second try? How does this show a way iteration can help produce better solutions?
Sometimes a problem is over-constrained—no solution can satisfy all the constraints. In such a case, it can be helpful to look at the need or problem definition in a different way. In the new-light problem, if no lighting fixture stayed within the cost constraint, you might look at other ways to improve safety. Perhaps a mirror, a lighter color of paint, and reflective strips might help. Perhaps an uneven floor is increasing the chance of someone tripping. Or perhaps another expense can be reduced to change the cost constraint of this problem.
Analyze In your notebook, use a diagram similar to Figure 15 to show how you moved between stages while working on the problem of paper or plastic bags.
Collaborate With a partner, review your definition(s) of the problem of paper or plastic bags. If your goals were to minimize cost, make the most efficient use of resources, and minimize environmental impact, how might you redefine the problem? Even though problems may seem isolated, the solutions are usually human activities that can have other impacts. When you finish solving a problem or have no more opportunities for optimization, it may still be useful to evaluate the solution and its impacts. You may learn something that will help with a later problem.
Analyze With a partner, discuss what you would do differently the next time you apply
the engineering design process and why. Lesson 1 Designing Solutions to Resource Problems
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CONTINUE YOUR EXPLORATION
Hands-On Lab Brightness and Color MATERIALS • lamps or sockets, identical (4) • incandescent light bulbs, 60 W and 100 W
FIGURE 16: Color temperature is based, in part, on the glowing filament of incandescent light bulbs. In such bulbs, the energy use determines the temperature, which mostly determines both the brightness and the color.
• LED light bulbs, approx. 800 lumens with different colors such as warm white and daylight • halogen or compact fluorescent bulbs (optional) • package information about the specific bulbs, such as energy required and price • photometer, color chart, or other tools (optional)
In this investigation, you will compare light bulbs to determine what characteristics to consider. Not all combinations of color and brightness may be available. In some types of bulbs, filters change the color by absorbing some light and wasting energy. PROCEDURE 1. Take safety precautions. Always unplug the lamps before inserting or removing a bulb. Use insulated gloves to handle bulbs that have been turned on. Handle the bulbs very gently to avoid breaking the glass. Do not touch a halogen bulb with bare skin (the oil in your skin can cause the bulb to break when hot). 2. Insert the bulbs in the lamps. Turn on the lamps. 3. Rank the bulbs from least bright to most bright and then from most red or yellow to most blue or white. 4. Record information about the bulbs, such as price, expected brightness, and energy use.
Research the effects of various light bulbs on the environment. Government or consumer sources may provide the most reliable information.
RESOURCE SOLUTIONS
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Analyze
1. Are your rankings of the brightnesses and colors consistent with the package information? What might account for any difference? 2. Which of the bulbs gives you the most light per unit of energy? 3. Explain how the properties of the bulbs are related to criteria such as minimizing cost and minimizing the effect on the environment.
ENGINEERING SPECIALIST
CROP LINES
Go online to choose one of these other three paths.
Image Credits:©ohsuriya/Fotolia Credits:
Language Arts Connection
EVALUATE
Lesson Self-Check CAN YOU EXPLAIN IT? Analyze Refer to the
FIGURE 17: Plastic and paper bags each have advantages and disadvantages.
notes in your Evidence Notebook to help you address the problem of which type of bag to use.
Image Credits: (l) ©Jeffrey Phelps/Aurora/Getty Images; (r) ©Diane Collins and Jordan Hollender/The Image Bank/Getty Images
Apply what you have learned about the engineering design process to look again at the choice between plastic bags and paper bags. Present an opinion about which type of bag should be used in stores in your community. Construct an argument to support that opinion. In your argument, address a range of factors. Take into account the need that is being addressed by the bags, the costs and benefits over the lifetime of the bags, and the effects on the community. For example, if you support plastic bags, consider how you might respond to people who complain about the sight of bags caught in trees, as in Figure 17. Think about other possible reactions, such as how store owners might react to the cost or convenience of your choice. In your argument, use at least one tool from the engineering design process. For example, you may wish to show the criteria and constraints for choosing bags. You may wish to put the possible solutions into a tradeoff matrix. Other people have made arguments about the choice between paper and plastic bags. Some arguments have changed over time as technology, costs, and public opinions have changed. You may wish to review these arguments or to gather specific information, such as costs or energy used in making different types of bags. Document any sources you use and evaluate the reliability of your sources, including the date of the information. Gather Evidence Based on what you know now, which type of bag do you
think should be used in stores in your community? Construct an argument to support your choice.
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EVALUATE
CHECKPOINTS Check Your Understanding
Use the following situation for problems 6–9:
1. Which of these are the goal(s) of natural resource management? Choose all that apply.
Suppose you are asked to come up with a design for a new mobile phone that uses solar energy as its energy source.
a. To stop the extraction and use of natural resources b. To reduce the effect of the use of resources on the environment c. To preserve nonrenewable natural resources d. To come up with solutions that balance costs and benefits e. To decrease the use of renewable natural resources 2. Do part of a life-cycle analysis for paper bags. Choose one of the stages shown in Figure 4, such as “refurbishing, reuse.” Describe the costs and benefits of paper bags in this stage. You might use relative terms, such as “much less than plastic bags,” rather than specific numbers. 3. In engineering, how is a problem typically defined? 4. The design of a solution usually involves iterations. When can a designer stop iterating? 5. What tools might be used to find an optimal solution?
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6. Give examples of one criterion and one constraint for this mobile phone. 7. Describe a risk that you would need to address. 8. Which battery would be best to use in the design? Support your answer. a. The most common battery used b. The least expensive battery c. The most efficient battery d. The smallest battery 9. What possible tradeoffs do you think you will make in choosing a battery for the design?
MAKE YOUR OWN STUDY GUIDE Use the following situation for problems 10–13: Suppose your school is not near your house and walking to school is not practical. You need to select or develop a way to get to and from school. 10. List several possible solutions that might help you to get to school while having the least undesirable effect on the environment. 11. Of the possible criteria and constraints, list several that you would evaluate in your comparison of possible solutions. 12. Compare riding a bike to school with either taking a bus or carpooling. Which of these natural resources would you be helping to conserve by riding a bike? Explain your choice(s).
In your Evidence Notebook, design a study guide that shows how the engineering design process can be used to identify and solve problems, including the management of natural resources. Remember to include the following in your study guide: • Support main ideas with details and examples. • Record ways to apply the skills that you develop. • Note how the use of natural resources is often part of designed solutions, though sometimes indirectly, such as through the cost of energy. Use the tools of defining criteria and constraints and of analyzing costs and benefits to help you take into account aspects of design that are not part of science, such as social values and personal preferences.
a. Fossil fuels b. Earth’s atmosphere c. Biodiversity d. Minerals 13. Suppose you decide that riding a bicycle to school is the best solution. How might you further refine, or optimize, this solution?
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3.2
Rock and Mineral Resources
The Mount Whaleback iron ore mine, which is located in western Australia, is the world’s largest open-pit mine.
CAN YOU EXPLAIN IT?
FIGURE 1: More than 70 different elements are found in the plastic and metal casing, touchscreen, battery, electronics, and circuitry that make up a smartphone.
Gather Evidence
Record evidence about rock and mineral resources. As you explore the lesson, gather evidence to help explain how the use of resources has changed over time, what resources are used today, how resources are mined, and the effects of mining on the environment. 128
Unit 3 Natural Resources
Predict All elements that make up the products we use every day come from living
things, like plants and animals, or non-living resources, such as rocks and minerals. Where do you think the elements that make up a smartphone come from? What rocks and minerals are they found in? What parts of the world do they come from?
Image Credits: ©John W Banagan/Photographer’s Choice/Getty Images; ©Scanrail/Getty Images
For many people, a smartphone has become part of everyday life. Like every other object or material that we use, smartphones are made of elements and compounds.
EXPLORATION 1
The History of Rock and Mineral Extraction Mining in the Ancient World Humans and their ancestors have been using rocks and minerals for more than 2.5 million years. Early humans fashioned stone tools from hard rocks such as flint, quartzite, and obsidian for protection, hunting, and preparing foods. Early humans also used native metals like gold and copper and even native iron from iron meteorites in places where they were available. People used pigments made of compounds such as iron oxide, manganese oxide, and charcoal for painting, salt for flavoring and preserving food, and clay to make durable pottery figures and containers.
Analyze Why do you
think people started using rocks, native metals, pigments, and clay much earlier than they started using non-native metals and alloys?
FIGURE 2: Metals such as copper, gold, lead, and mercury, which are relatively easy to extract from rocks, were mined in the ancient world.
ATLANTIC OCEAN Las Medulas, Spain
Black Sea
Attica, Greece
Mediterranean Sea
Skouriotissa, Cyprus
Timna, Israel
Image Credits: (r) ©moris kushelevitch/Alamy; (l) ©NoraDoa/Fotolia
km 0 mi 0
250
N
500 250
500
W
E S
Around 4000 BCE, modern humans began smelting—heating rocks to extract metals such as copper, tin, and lead. They also began making alloys, or mixtures of metals, such as bronze. Bronze is a mixture of copper and tin and is much harder and stronger than either copper or tin alone. By 1500 BCE, people had figured out how to extract iron, a much stronger but much harder-to-work metal, from iron-rich rocks.
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FIGURE 3: Native American tools
These stone axes were recovered from the Etowah Indian Mounds Historic Site near Cartersville, Georgia and date from approximately 1200 to 1000 CE.
Analyze Compare the
properties and uses of materials such as quartzite and flint, coarse-grained igneous cobbles, and native copper. How were the ways that the materials were used related to their properties?
Native American Quarrying and Mining Thousands of years before Europeans settled in North America, Native Americans were using a wide variety of rock and mineral resources for tools, weapons, pottery, building materials, jewelry, and artwork. As in other parts of the world, the specific materials used depended on what was available locally or through trade, what methods had been developed to extract and use the materials, and what the need was for certain materials with certain properties. For example, as early as 10 000 years ago, people were quarrying quartzite, a very hard metamorphic rock that breaks into sharp pieces that are ideal for use in knives and spears. Obsidian and flint were also used for weapons. Other types of hard rocks were used for grinding and hammering. Beginning around 7000 years ago, Native Americans mined copper in Michigan from both surface pits and underground shafts. The malleable copper was used for making items like fishhooks, spear points, and jewelry, and was also used for trade. Soft and colorful minerals such as turquoise were used for beads and jewelry. Native Americans also used clays for pottery and mined or extracted salt for cooking.
Rock and Mineral Resource Distribution Rock and mineral resources include all rocks, sediments, minerals, and native elements from Earth’s crust that people use to make things such as structures, tools, medicines, weapons, and artwork. Rock and mineral resources include rocks such as sandstone and granite for building; limestone for making cement; sand for construction, to make glass, and to replenish beaches; salt for flavoring food and melting snow; clays for ceramics; galena for lead; and bauxite for aluminum in cans and airplanes. FIGURE 4: World Mineral Production from 2005–2009: This map shows the relative amounts of major metals mined in various countries around the world.
CANADA
MEXICO COLOMBIA PERU
RUSSIA KAZAKHSTAN
UZBEKISTAN
IRAN CUBA JAMAICA GUINEA INDIA GHANA SURINAME CONGO BRAZIL ZAMBIA INDONESIA ZIMBABWE
CHILE
SOUTH AFRICA
Aluminum Iron
Copper Nickel
CHINA
PHILIPPINES NEW CALEDONIA
AUSTRALIA
Gold Platinum
Model If you had maps of resource production for different decades, describe how
you could use them to model resource production and use. How could you use them to predict future resource discovery?
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Image Credits: (t) ©Millard H. Sharp/Science Source
UNITED STATES
UKRAINE
Exports/Imports In early prehistoric times, people were limited to using the rock and mineral resources found nearby. Thus, different populations of people likely used different resources, and different technologies, artwork, and cultures developed as a result. Over time, however, as human populations grew and spread, resources also spread through trade, plunder, and resettlement. Today, although rock and mineral resources are not evenly distributed, people around the world generally do need or want the same resources. There is now a global market for rock and mineral resources, and unlike thousands of years ago, we now have a complex transportation system that makes trade possible.
United States Net Import Reliance, 2008–2011 FIGURE 5: The United States produces only some of the mineral resources that it uses. It imports the rest from other countries. In 2014, the United States exported $153 billion worth of minerals and metals, but imported $205 billion.
U.S. Net Import Reliance, 2008-2011
Commodity Bauxite and Alumina Indium Niobium Scandium Tantalum Gallium Vanadium Platinum Germanium Diamond (dust, grit, powder) Cobalt Titanium Mineral Concentrates Zinc Silver Nickel Tungsten Copper Salt Iron and steel
Source: U.S. Geological Survey
Major Import Sources Jamaica, Brazil, Guinea, Australia China, Canada, Japan, Belgium Brazil, Canada, Germany China China, Estonia, Germany Germany, UK, China, Canada Rep. of Korea, Canada, Austria Germany, South Africa, UK, Canada China, Belgium, Russia, Germany China, Ireland, Rep. of Korea, Russia China, Norway, Russia, Finland South Africa, Australia, Canada Canada, Mexico, Peru, Spain Mexico, Canada, Peru, Poland Canada, Russia, Australia, Norway China, Bolivia, Canada, Germany Chile, Canada, Peru, Mexico Canada, Chile, Mexico, Bahamas Canada, EU, Mexico, Rep. of Korea
0 20 40 60 80 100 Percent
For any given type of resource, there are countries that produce more of the resource than they use, and those that produce less than they use. Those countries that produce more than they need export to those who produce less. Importing countries rely heavily on exporting countries for raw materials, while exporters rely on importers to buy what they produce.
Explain What natural and human factors have influenced the rock and mineral resources people have used and how resources have been used in different places over time? Use evidence from the lesson and other sources to support your claims.
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EXPLORATION 2
Minerals for New Technologies New Uses for Minerals The use of rock and mineral resources has changed over time as people have discovered new elements and mineral deposits, new properties of elements and compounds, and new ways of extracting and processing materials. It has also changed as the demand for certain materials, products, and capabilities has changed. Minerals that contain rare earth elements—certain heavy elements that react very easily with other elements—make it possible to meet the demand for products like cars that cause less pollution, medical tools that can better diagnose and treat illnesses and injuries, airplanes that can fly faster than the speed of sound, and electronics that can monitor our homes and bodies. Many of these minerals are referred to as “critical and strategic” minerals because they are essential for agriculture, medical devices, electronics, renewable energy, national defense, and common household items.
Mineral Use in Electronics Electrical devices transform electricity into other forms of energy, such as heat, light, and motion. Toasters, flashlights, and fans are all electrical devices. Electronics, however, are devices that use complex circuits to manipulate the flow of electrons to perform a wide variety of tasks, such as sensing, analyzing, and transmitting information. Computers, phones, digital cameras, and television displays all include electronics. One of the key components of the electronics we use today are rare earth elements. Rare earth elements (REEs), such as neodymium, praseodymium, and dysprosium, are used to make extremely strong magnets that can also withstand high temperatures in electric motors and wind turbines. Europium, yttrium, and terbium have luminescent properties that make them ideal for computer monitors and smartphone screens. Lanthanum is important in the rechargeable batteries used in many consumer electronics. Analyze When designing
FIGURE 6: The display on a smartwatch uses luminescent rare earth elements.
Image Credits: ©Leo Lintang/Fotolia
electronics, engineers need to consider the specific physical, chemical, electrical, and magnetic properties of elements. What properties do you think are particularly important for elements used in electronics?
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Mineral Use in Hybrid Cars A typical passenger car has a mass of about 1500 kg. More than half that weight is steel, an inexpensive and strong alloy of iron and other elements, such as carbon, manganese, and chromium, which is used to make the frame, doors, and engine. Manufacturing a car also requires resources like aluminum for the wheels and body panels, silica for the glass windows, asbestos used in brake pads, mica used in shock absorbers, copper in the wiring, tungsten for the light bulb filaments, cerium in catalytic converters, gallium for the mirrors, and antimony to make the upholstery fire resistant. Each material is chosen based on its unique set of properties, its availability, and its cost. Aluminum, for example, is lighter and resists impacts and corrosion better than steel, but it is also more expensive. As a result, it is still only used in the frames of expensive cars, while most other cars are still made of steel.
Predict If the demand for
cars with smart technology and green technology continues to increase, how will this affect the demand for REEs? How could it affect the supply of REEs? How would it affect the overall abundance of REEs on Earth?
FIGURE 7: This electric car is powered by 102 lithium ion batteries, which give it a range of 340 km and a top speed of 115 km/hr.
Modern cars also include color touchscreens, computer chips, and other electronic components, and thus use many of the same elements as smartphones, including rare earth elements (REEs).
Image Credits: ©Paul Rapson/Science Source
With the increasing concern about the effects of burning gasoline on the environment, more and more people are choosing to buy “green” vehicles like hybrids. Hybrid cars use less gasoline than traditional cars because they run on an electric motor as well as a gasoline engine. The electric motor relies on a battery that is recharged as the car moves and brakes. Hybrid cars require about twice the amount of REEs as a traditional car. The electric motor and generator include neodymium, praseodymium, dysprosium, and terbium, while a hybrid battery uses lanthanum, neodymium, and cerium or lithium, cobalt, and graphite. Although REEs are found around the world, most REE production is currently in China.
Mineral Use in Aerospace Technology As with cars and electronic devices, the technology of air- and spacecraft has changed significantly over the past 100 years in large part because of the increased availability of resources and the development of new materials and components that have been designed from those resources. The materials that make up aircraft need to be lightweight, strong, flexible, and resistant to temperature extremes. The communication and control systems inside the craft need to be electrically conductive.
Analyze What rocks and minerals do you think the materials used to build a plane come from?
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133
FIGURE 8: The F-22 fighter jet is composed of titanium, carbonfiber composite, aluminum, and thermoplastic. Titanium is used because it is relatively lightweight and strong. Carbon-fiber composites are used for the body frame and for skin panels. Thermoplastics are used for the landing gear and weapons bay doors.
Modern airplane bodies are made mostly of light but strong materials such as aluminum, titanium, carbon fiber, and fiberglass. Engine components require alloys of metals like rhenium, cobalt, nickel, niobium, hafnium, and titanium, which are able to withstand high temperatures. Flight controls include samarium (a rare earth element) and cobalt. Stealth technology uses the rare earth elements samarium and neodymium, as well as cobalt, nickel, and titanium. Modern aircraft also include all of the elements found in everyday electronic displays, communication systems, and computer processors.
Technology and Society
Carbon Fiber Carbon fibers are long, thin strands of carbon atoms that can be twisted and woven together into fabric and combined with other materials like resin to make a composite. Like many carbon-based materials, the carbon that makes up carbon fiber generally starts out as petroleum deep underground.
Carbon fiber was first invented in 1958, and by the mid-1960s, engineers had developed a process to manufacture it on a large scale. But manufacturing carbon fiber is still very slow and energy intensive. It is therefore also very expensive. Right now, although they are much more energy efficient, very few carbon-fiber cars are manufactured because very few people can afford them. As a result, engineers are working on improving not only carbon-fiber fabric design, but also the manufacturing process.
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Image Credits: ©William Yardley/Fotolia
Carbon fiber and carbon-fiber composites have a number of important properties that make them useful for many different types of products, including sporting goods, automobiles, and airplanes. Carbon fiber is resistant to corrosion, expands and contracts very little with changes in temperature, and is very light, rigid, and strong for its weight. Cars made of carbon fiber, for example, can weigh about half as much as cars with steel bodies.
Minerals Used in Medical Technology Collaborate With a partner, try to identify elements and compounds that are used in medical devices that you are familiar with.
Numerous elements and compounds derived from rocks and minerals are used to make the wide variety of medical devices that are used to diagnose and treat illnesses and injuries. For example, stainless steel (an alloy of iron and chromium) is used in numerous surgical devices and in implants. Gold is used in life-support devices, pacemakers, and heart stents. Together with silver, gold is used in CAT scan devices. Lithium is widely used in pacemakers, defibrillator machines, and other types of portable electronic equipment. Other metals, such as aluminum, nickel, titanium, and cobalt, are used in joint replacement, and rare earth elements are used to produce powerful magnetic fields used in medical imaging devices such as MRIs. FIGURE 9: Medical devices contain elements such as rare earth elements and lithium. a MRIs enable doctors to
b A defibrillator is an electronic
diagnose illnesses and injuries that otherwise would be harder to detect.
device that sends an electric shock to the heart to stop an irregular heartbeat.
Rare Earth Elements in Technology Although rare earth elements are not truly rare, they are generally not concentrated enough to be mined profitably. When they are concentrated, they form minerals that contain REEs, such as bastnäsite and monazite, which are found in relatively rare types of igneous rocks in the continental crust. Until recently, it has been difficult to extract and separate REEs from the rocks and minerals and from each other. FIGURE 10: Rare earth elements
21
39
Scandium
Yttrium
Sc 57
Image Credits: (l) ©zlikovec/Fotolia (r) ©phillip kinsey/Fotolia
La
Lanthanum
Y
58
Ce Cerium
59
Pr
Praseodymium
60
Nd
Neodymium
61
Pm
Promethium
62
Sm Samarium
63
Eu
Europium
64
Gd
Gadolinium
65
Tb Terbium
66
Dy
Dysprosium
67
Ho Holmium
68
Er Erbium
69
Tm Thulium
70
Yb
Ytterbium
71
Lu Lutetium
Small deposits of REEs are found throughout the world, but the vast majority of REE production is currently in China. Because REEs have become essential in so many important applications, from everyday consumer electronics to medical, renewable energy, and defense technology, the United States considers the rare earth minerals to be critical and strategic minerals.
Analyze The United States must import more than 75% of the REEs that it uses. In what
ways could reliance on other countries for rock and mineral resources be risky? How could the United States reduce those risks? Lesson 2 Rock and Mineral Resources
135
EXPLORATION 3
Rock and Mineral Extraction The type of mining, or the method used to extract a particular rock or mineral resource, depends on the properties of the resource and the size, shape, concentration, and location of the deposit.
Surface Mining Methods Deposits that are located on land and on or near the surface can be extracted using a surface mine. Some methods of surface mining include open-pit mining, quarrying, strip mining, hydraulic mining, and solar evaporation mining. FIGURE 11: Methods for Extracting Rock and Mineral Resources
a
An open-pit copper mine in South Africa
b
A solar evaporation pond for mining salt in India
Strip Mining Sedimentary resources such as phosphates, salt, and aluminum commonly exist as flat layers beneath the surface. These can be extracted using strip mining, in which successive horizontal strips of overlying rock and resources are removed. As overlying rock is removed, it is piled on top of the previous strip.
Explain Why can’t all minerals be mined using solar evaporation ponds? Why can’t all be extracted using hydraulic mining? 136
Unit 3 Natural Resources
Hydraulic Mining Placer deposits are loose ancient or modern river and stream sediments that contain dense and valuable minerals such as gold and platinum, and gemstones such as diamond, ruby, and sapphire. Many placers are mined using hydraulic mining, which involves loosening the sediments with high-pressure jets of water. The sediments then move though a system of sluice boxes designed to remove the valuable minerals. Solar Evaporation Ponds Minerals that are soluble in water can be extracted from ground and surface water using evaporation. Salt water is pumped from underground or channeled from the surface into shallow ponds in hot, dry climates. Minerals crystallize as the water evaporates. Once the pond is dry, the minerals are harvested.
Image Credits: (l) ©sfmthd/Fotolia; (r) ©Premraj K.P./Alamy
Open-Pit Mines As the name suggests, open-pit mines are giant holes in the ground. Explosives are used to break apart the rock, while giant trucks are used to haul it out of the mine. Some open-pit mining involves removing layers of rock or sediment above to expose the deposit. In some areas, so much rock is removed that the process is referred to as mountaintop removal. Copper and iron are commonly extracted from open-pit mines. Open-pit mines for sand, gravel, and building stones, such as granite and marble, are often referred to as quarries.
Subsurface Mining Methods Subsurface mines are much more expensive to operate than surface mines and thus are reserved for more valuable deposits. There are several methods of subsurface mining. The method chosen depends on natural factors such as the properties of the resource being mined; the size, shape, and depth of the ore body; the strength of the surrounding rock; and the amount of groundwater present. It also depends on human factors such as labor costs, environmental laws, safety regulations, and the market price of the resource. Metal and other valuable minerals are extracted from ore, a natural material made of one or more minerals.
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Hands-On Lab Copper Recovery Extract solid
copper from an iron nail.
FIGURE 12: In a room-and-pillar mine, columns of ore are left over to support the ceiling and keep the mine from caving in.
pillars
vertical benching benching at thicker parts of ore body
connecting drift front benching
Explain Planning a subsurface mining operation often requires the expertise of both
geologists and civil engineers. How are these roles important? What could happen if an operation were not planned properly? Minerals that dissolve easily can be extracted using solution mining. Solution mining involves pumping hot water or acidic solvents down into the ground where they dissolve minerals like salt, sulfur, gold, and copper. The mineral-rich brine is then pumped up to the surface, where it can be processed. If the rock surrounding an ore body is very hard, ore can be removed using block caving or stoping. In these methods, workers drill and blast from below, creating a pile of broken ore on the floor of the mine. The broken rock is then transported to the surface with machinery. In some mines, stoping creates giant underground rooms. In others, waste rock is poured or pumped back down into the mine to fill the empty space. This cut-and-fill method helps get rid of the waste and also support the mine. The room-and-pillar method is often used for flat sedimentary ore bodies with a relatively weak or fractured sedimentary layer above. Rather than removing all of the ore, which would likely result in a mine collapse, rooms of ore are removed while pillars of ore are left standing to support the rock above. Lesson 2 Rock and Mineral Resources
137
Marine Mining Predict How do you
think marine mining can affect habitats on the seafloor and in the water column above the mining operation?
Some resources are concentrated in sediments on the seafloor. Spherical nodules on the deep seafloor are rich in metals like manganese, cobalt, and nickel. Rich deposits of copper, lead, zinc, cobalt, gold, and rare earth elements can form around submarine hot springs on the seafloor. Most of these resources lie in water that is 500 m or more below sea level. Therefore, the challenge of marine mining is the technological difficulty associated with extracting mineral deposits from deep water. As of yet, however, the only resource worth the great expense of marine mining is diamond. Offshore diamond mining takes place primarily off the coast of southern Africa in waters that are less than 200 m deep. Diamond-rich sediments weather out of rock on the continent and are then transported by flowing water into the ocean, where they settle out with other sediments on the seafloor. Diamond mining ships drill and suck up diamond-rich sediments from the seafloor and transport them to a sorting plant onboard the ship. Waste is then dumped back out into the ocean.
with a classmate, research experimental deep-sea mining that could occur in the Bismarck Sea off of Papua New Guinea. With your partner, conduct a tradeoff analysis of such a mining operation. What might be some of the benefits? What might be some negative impacts? Suggest some criteria and constraints that might help to address the negative impacts of such a mining operation and prepare a short presentation for your class.
In the future, marine mining may focus primarily on mining minerals containing copper, iron, and zinc from deep-sea hydrothermal vents. At present, hydrothermal vents in the western South Pacfic Ocean are of particular interest to mining companies. Papua New Guinea is the only country to have allowed this form of mining in their waters. However, the potential environmental effects of this mining is raising concerns throughout the region. This is partly due to the fact that deep-sea vents have unique ecosystems. They provide habitats for little-known, deep-sea organisms that obtain their energy from chemicals rather than sunlight. FIGURE 13: This offshore mining ship is exploring the seafloor sediment for diamonds off of Namibia in southwest Africa.
Analyze Different forms of mining have different economic, social, safety, and
environmental risks and benefits. Compare the risks and benefits of one form of surface mining and one form of subsurface mining. Think about the costs and hazards, as well as the potential benefits in terms of the local or national economy or in terms of our ability to make new products. 138
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Image Credits: ©Ulrich Doering/Alamy
Collaborate Together
EXPLORATION 4
Impacts of Mineral Use Potential Effects of Mining Mining (along with recycling of previously mined materials) is essential in order to meet many of the needs and wants of today’s society. Recycling is the recovery of useful materials from waste. However, mining and processing of rock and mineral resources also has very serious environmental effects.
Explain What factors
influence the effects of mining on the environment?
FIGURE 14: Both surface and subsurface mining can negatively impact the environment.
Image Credits: (l) ©alexandrumagurean/iStock/Getty Images Plus/Getty Images; (r) ©Ashley Cooper/Alamy
a
Acid mine drainage from a copper mine in Romania has negatively affected this body of water.
b
This hole opened up in the backyard of a home in Egremont, England when an old mine shaft collapsed.
Surface mining can destroy habitats and displace wildlife; send dust into the air, causing air pollution; and result in leaching, erosion, and subsequent pollution of streams, rivers, and other bodies of water. The vibrations and noise from drilling, explosions, and heavy trucks used in surface mining can also be very disruptive to people and other living things. Subsurface mining can pollute groundwater resources and can cause land subsidence such as that shown in Figure 14b. Mineral processing— the processes used to remove the valuable components from the ore rocks and minerals after they have been mined—can also cause land, water, and air pollution. Mining can also have negative effects on individual mine workers. Mines that are not engineered, monitored, and maintained properly can collapse, flood, or overheat. Poor ventilation can result in the buildup of toxic and explosive gases and dust. The specific effects of a mining operation depend on factors such as the mining methods that are used, the topography and climate of the area, the structure and chemistry of the ore body and the surrounding rocks, and the size of the operation. For example, a copper mine and smelting plant are likely to cause much more air and water pollution than a granite building-stone quarry.
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Hands-On Lab Investigating Ore Deposits Model a geophysical
survey to find metal ore deposits, and consider the costs and benefits of decisions.
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139
Stability and Change Explain Mining
operations can last for many years. How can the benefits of these operations be weighed against potential long-term environmental and social impacts?
The Social Effects of Mining Mining can be an important part of a nation’s economy. Mining projects provide jobs to local people in the community and wealth to the region in general. But in many cases, these short-term benefits are outweighed by other effects. In recent years, concerns over the environmental and social effects of mining have led people to protest mining operations. In some cases, protestors have been able to stall or stop mining projects completely before they’ve even begun. For example, in 2013 an open-pit gold and silver mining project in the Andes Mountains of South America was stalled over concerns that mining would destroy glaciers and would affect indigenous people living in the area. In Romania, people protested plans to open an ancient gold and silver mine. They were concerned not only about cyanide used in the mining process, but also because the operation would destroy an archeological site: the oldest Roman gold mine galleries in the world. People in Greece protested a gold mine project because of concerns about groundwater and air pollution and also because they feared it would have negative effects on other aspects of the local economy, like tourism, fishing, farming, and beekeeping.
Regulation and Compliance In order to reduce the effects of mining on the environment, countries have laws and regulations that govern how mines must be operated. The laws differ from country to country—laws are much stricter in some countries than in others. In the United States, mining companies must comply with laws such as the Clean Air Act, the Safe Drinking Water Act, the Solid Waste Disposal Act, the Endangered Species and Migratory Bird Treaty Acts, as well as the Surface Mining Control and Reclamation Act. Mining companies must also abide by strict health and safety regulations to protect people working in and around mines and processing facilities. In order to operate a mine in the United States, a company must also have a reclamation plan. Reclamation is the process of returning the land to its former environmental condition. A reclamation plan describes exactly how the company plans to restore the landscape and ecosystems that the mine disrupted. Reclaimed surface mines have been turned into pasture, forestland, playing fields, and golf courses. Quarries are often flooded and turned into recreational lakes. In order to ensure that a mining company abides by all standards and reclaims the site as planned, money is set aside in the form of a bond. If a company does not mine and reclaim a site according to the standards required by its permits, the company must give the bonds to the states, which use the funds to reclaim the site. Collaborate Choose one type of mine. How might this type of mine and mining
operation affect the environment? How could the land be reclaimed after the mine ceases operating?
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Hands-On Lab
Reclamation PROCEDURE
MATERIALS
1. Use a plastic spoon to remove the first layer of gelatin from a multilayered gelatin dessert cup and place it into a small bowl.
• bowl, small
2. Remove the next layer of gelatin and discard it.
• gelatin desert cup, multilayered
3. Restore the dessert cup by replacing the first layer of gelatin.
• spoon, plastic
A N A L Y Z E 1. What does the first layer of gelatin on the restored dessert cup represent? 2. Does the “reclaimed” dessert cup resemble the original, untouched dessert cup? 3. What factors would you address to make reclamation more successful?
Minimizing the Impact of Mineral Extraction
Image Credits: (l) ©fstop123/E+/Getty Images; (r) ©Patrickmorrisseyphoto/iStock/Getty Images Plus/Getty Images
Decreasing the amount of a particular resource that must be mined to meet demands can reduce the negative effects of mining. For example, when engineers improve the ability to extract a particular metal from a rock, less rock needs to be mined. Materials that can be mined and processed with less damage to the environment can be substituted for those that cause more damage. Everyone can help significantly reduce the need for mining simply by reducing our consumption, reusing products when possible, and recycling materials. Building smaller houses, recycling aluminum cans and glass jars, and buying a used car instead of a new one are all ways to reduce the effects of mining on the environment. FIGURE 15: Recycling materials such as trash and scrap metal help to reduce the demand for resources that must be mined.
a This girl is helping to recycle items that have been carelessly
disposed of in a neighborhood park.
b Scrap metal can be recycled for many elements, including
iron, titanium, tungsten, vanadium, zinc, and zirconium.
Predict How could improving recycling rates and recycling technology influence the
effects of mining around the world? Lesson 2 Rock and Mineral Resources
141
CONTINUE YOUR EXPLORATION
Careers in Science Recycling Technician FIGURE 16: A technician is taking apart a television set in order to recycle parts at this technology center in Katō, Japan.
Mining rock and mineral resources is expensive in terms of both dollars and cost to the environment. While some resources are plentiful, others are in very limited supply. Recycling common materials like aluminum, glass, and steel, as well as less abundant materials such as rare earth elements, is important for both the environment and the economy. Recycling technicians play a key role in this process. Recycling technicians may carry out a variety of jobs related to recycling. Some recycling technicians work for large businesses, universities, and government offices to create and manage recycling programs and motivate people to recycle. Others work for waste management companies to ensure that recycling is being collected properly and that people who want to recycle have what they need. Some recycling technicians work at recycling plants to make sure the materials are sorted properly.
recycling in a specific community. Do the benefits of recycling outweigh the costs? Research the societal and environmental benefits as well as the financial costs and benefits of recycling in the community. Use reliable sources, such as government agencies, educational institutions, and personal interviews with authorities. When drawing evidence from these sources, ask yourself: Are the facts verifiable—that is, can they be proved to be true? Is the source an expert? Finally, develop your argument and present it to your peers. Be sure to cite specific evidence to support your claims.
GPS FOR UNDERGROUND MINING
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CONFLICT MINERALS
Go online to choose one of these other paths.
Image Credits: ©Yuriko Nakao/Bloomberg/Getty Images
Language Arts Connection Gather evidence to develop an argument for
EVALUATE
Lesson Self-Check CAN YOU EXPLAIN IT? FIGURE 17: A smartphone is composed of many different elements.
Image Credits: (b) ©Scanrail/Getty Images
More than 70 different elements are found in the plastic and metal casing, touchscreen, battery, electronics, and circuitry that make up a smartphone. Each of these elements comes from either living things or non-living resources such as rocks and minerals. The silica that makes up the glass and the silicon in the computer chips come from quartz sand. The aluminum that makes the glass shatter resistant comes from an aluminum ore called bauxite. Rare earth elements used to make the magnets in the speaker and microphone, the mechanism that causes the phone to vibrate, and the bright colors on the screen come from minerals like bastnäsite and monazite, which are found in some igneous rocks. Indium used to make the touchscreen is found in deposits along with copper that is used for wiring and lead used for solder. Tin in the touchscreen and that becomes the solder that binds the components together comes from the mineral cassiterite, which is found in igneous rocks and some sediments. Lithium used in the rechargeable batteries comes from lithium-rich brines and is mined using solar evaporation ponds. The smartphone case can be made of carbon from oil deposits or graphite deposits. Explain All elements that make up the products we use every day come from living
things, like plants and animals, or non-living resources, such as rocks and minerals. Where do you think the elements that make up a smartphone come from? What rocks and minerals are they found in? What parts of the world do they come from?
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EVALUATE
CHECKPOINTS Check Your Understanding 1. Which of the following statements about rock and mineral resources is true? Choose all that apply. a. There are no valuable minerals in Antarctica. b. Rock and mineral resources are distributed evenly across the globe. c. Rock and mineral resources are distributed randomly across the globe. d. Most of the deposits shown on the Figure 4 resource map were used by prehistoric people.
5. Make a table of the rock and mineral resources that might be used in constructing a house. Include as columns in the table where you are likely to find these resources, how they might be mined or extracted, what the effect of extraction might be on the environment, and how the effects on the environment could be minimized. 6. Describe at least two effects that marine mining may have on the offshore environment. 7. Which of the following is not a surface-mining method? a. solar evaportion
e. The cost of extracting valuable minerals is the same everywhere in the world.
b. hydraulic mining
f. The value of a rock and mineral deposit depends on its size, shape, location, and concentration.
d. strip mining
2. Which of the following statements about REEs are true? Choose all that apply. a. REEs can be mined profitably because they are easy to extract from rocks. b. REEs are considered to be critical and strategic minerals in the United State. c. The majority of REE production is currently in China. d. REEs are extracted from igneous rocks that occur commonly in Earth’s crust. 3. The production of REEs has increased more than 1000% since 1965. Which is most likely driving the change in REE production? a. Increasing demand for organic foods b. Increasing demand for consumer electronics c. Increasing demand for better-insulated houses d. Increasing demand for drinks in unbreakable containers 4. The change in production of REEs has probably also resulted in which of the following? Choose all that apply. a. Increase in the abundance of REEs on Earth b. Decrease in water pollution near REE mines
c. room-and-pillar mining
8. Which of the following statements are true about mineral production in the United States? Choose all that apply. a. The United States produces the majority of the mineral resources that it uses. b. The United States is a major exporter of REEs. c. Among the major suppliers of mineral resources to the United States are China and Canada. d. The United States exports more mineral resources than it imports. 9. Which of the following mineral resources can be extracted using the solar evaporation method of mining? a. salt (halite) b. gold c. diamond d. copper 10. Which of the following statements are true about mine reclamation in the United State? Choose all that apply. a. Mining companies in the United State must set aside money for reclamation in the form of a bond. b. To operate a mine in the United State, a mining company must have a reclamation plan.
c. Increase in habitat destruction as a result of mining
c. Open-pit mines are often flooded and turned into recreational lakes.
d. Increase in air pollution near mines and processing plants
d. Mining companies in the United State must comply with a number of environmental laws. 11. Briefly describe how Native Americans used the mineral resources that they mined and quarried.
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12. Titanium is light but strong. It has an important use in which of the following applications? Choose all that apply. a. joint replacement b. rechargeable batteries for hybrid cars c. magnets in electronic and medical equipment d. aircraft bodies 13. Solution mining is used in which of the following situations? a. when there is an ore body with a weak or fractured layer above it b. when very hard rock surrounds an ore body c. when there is sediment that needs to be loosened using high water pressure
18. List some of the factors that determine which type of mining would be used to extract a specific mineral resource. Use examples of both surface mining methods and subsurface mining methods. 19. Discuss some ways that people can reduce the impact of mineral resource extraction. 20. Explain what is meant by a critical and strategic mineral. 21. Explain how carbon fiber is produced and some of its applications in modern technology. 22. Describe a particular piece of modern technology that you want to build, the properties that you wish the piece to have, and the resources that you would build it from.
d. when there are minerals that dissolve easily 14. Which of the following are important reasons why we use REEs in electronics technology today? Choose all that apply. a. REEs are extremely light b. REEs resist impact and corrosion better than steel c. some REEs have luminescent properties d. some REEs can be used to make strong magnets 15. Which of the following were important mining localities in the ancient world? Choose all that apply. a. Timna, Israel b. Las Medulas, Spain c. Attica, Greece d. Skouriotissa, Cyprus 16. Which of the following are important mineral resources that can be obtained by hydraulic mining? Choose all that apply. a. gold b. ruby
MAKE YOUR OWN STUDY GUIDE In your Evidence Notebook, design a study guide that supports the main ideas from this lesson: Remember to include the following in your study guide: • Support main ideas with details and examples. • Record explanations for the phenomena you investigated. • Describe how new technologies can have deep impacts on society and the environment, including some impacts that were not anticipated. • Explain why science and technology may raise ethical issues for which science, by itself, does not provide answers and solutions. • Explain why the analysis of costs and benefits is a critical aspect of decisions about technology.
c. salt (halite) d. manganese 17. Describe some scenarios where people have opposed building a mine at a specific location.
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3.3
Energy Resources
Gather Evidence As
you explore the lesson, gather evidence on the pros and cons of different energy resources.
CAN YOU EXPLAIN IT? FIGURE 1: Natural gas can be extracted from Earth by the hydraulic fracturing method.
Hydraulic fracturing, also called fracking, is the process by which materials are pumped underground to break up rock and release oil or natural gas. The materials include large amounts of water, sand and chemicals. Natural gas and other fossil fuels take millions of years to form and therefore exist in limited amounts. Once a fossil fuel is used, it cannot be quickly replaced. At this time, most of the energy used in the United States is generated using fossil fuels, such as the natural gas extracted by hydraulic fracturing. The natural gas is used primarily to generate electricity. It also is used to heat about half the homes in the United States. Hydraulic fracturing, however, has troubling environmental consequences that will be discussed in more detail later in this lesson. Does the environmental impact of hydraulic fracturing outweigh the benefit of obtaining natural gas for energy? Predict How might hydraulic fracturing be used to obtain energy from Earth’s subsurface?
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Image Credits: (t) ©Ethan Miller/Getty Images ; (b) ©Yarygin/Shutterstock
The Crescent Dunes Solar Energy Plant, located about 225 miles northwest of Las Vegas, can generate energy day and night. It can generate enough electricity to power 75 ,000 homes.
EXPLORATION 1
Petroleum and Natural Gas Fossil fuels are compounds that contain hydrogen and carbon atoms and formed from the remains of living things. Because of their organic origin, coal, petroleum, and natural gas are known as fossil fuels. Fossilinfuels considered nonrenewable. Energy Consumption the are United States, 1850-2014
Percentage of energy use
100
FIGURE 2: Energy consumption in the United States between 1850 and 2014
Wood Coal Petroleum Natural gas Nuclear Hydroelectric Other renewables
80 60 40 20 0 1850
1890
1930 Year
1970
2014
The Importance of Petroleum and Natural Gas Observe How are
Petroleum is the largest source of energy used today and is a fundamental component of many consumer and commercial products. The majority of petroleum recovered from Earth is used to produce gasoline and diesel fuels for transportation.
petroleum and natural gas typically used in the United States?
Natural gas is the second largest source of energy used today and accounts for about 24% of energy in the United States. Most natural gas is used to generate electricity, but natural gas is also used for industrial, commercial, and residential applications, such as heating and cooking. Products Made from a Barrel Consumption of Natural Gas,
Products of Made from a Barrel Crude Oil Products from aaBarrel ProductsMade Made fromOil Barrel of Crude FIGURE 3: Petroleum products and natural gas uses ofofCrude CrudeOil Oil
3% 3% 4% 3% 3% 4% 4% 4%
10% 10% 10% 10% 13% 13% 13% 13% 23% 23% 23% 23% 47% 47% 47% 47%
Consumption of Natural Gas, Unitedofof States, 2012 Consumption Natural Gas, Consumption Natural Gas, United States, 2012 United 2012 UnitedStates, States,0.1% 2012 3% 3% 0.1% 3% 3% 0.1% 0.1% 12% 12% 12% 12% 38% 17% 38% 17% 38% 38% 17% 17%
Asphalt Asphalt Liquified petroleum Asphalt Asphalt Liquified petroleum Jet Fuel Liquified petroleum Liquified petroleum Jet Fuel Other products Jet Fuel JetOther Fuel products Diesel fuel and heating oil Other products Other products Diesel fuel and heating oil Gasoline Diesel fuel Diesel fueland andheating heatingoil oil Gasoline Gasoline Gasoline Source: U.S. Department of Energy
30% 30% 30% 30%
Source: Energy Information Administration Source: Source:Energy EnergyInformation InformationAdministration Administration
Source: U.S. Department of Energy Source: Source:U.S. U.S.Department DepartmentofofEnergy Energy a
Many products that are used every day are made from petroleum.
Electric power Electric power Industrial Electric power Electric power Industrial Residential Industrial Industrial Residential Commercial Residential Residential Commercial Pipeline and distribution Commercial Commercial Pipeline and distribution Vehicle fuel Pipeline and distribution Pipeline and distribution Vehicle fuel Vehicle fuel Vehicle fuelInformation Administration Source: Energy
b
Most of the natural gas in the United States is used to generate electricity.
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Petroleum and Natural Gas Reservoirs Explain What are the
conditions necessary to produce a reservoir for petroleum or natural gas?
Petroleum and natural gas form in reservoirs, or pockets, in Earth’s interior. Three components are required to produce these reservoirs. The first component is heat. The source rock, rich in organic material, must be located deep enough inside Earth to be subjected to temperatures sufficient to convert the organic carbon into petroleum. The second component is a permeable layer. A porous, permeable reservoir rock, such as sandstone or limestone, which contains pore large enough and with enough connections to serve as storage an migration sites for petroleum to accumulate is needed. The third component is an impermeable layer. A dense layer of rock must be located above the porous permeable layer to prevent petroleum from moving to the surface.
FIGURE 4: Petroleum and natural gas are found in pockets under layers of rock and sediment in Earth’s interior.
gas-saturated sandstone oil and gas well oil-saturated sandstone sandstone
limestone
shale (impermeable)
water-saturated sandstone (porous)
shale
sandstone
Extracting Petroleum and Natural Gas FIGURE 5: This cross-section illustrates how carbon dioxide and water can be used to flush residual petroleum from the subsurface between wells during enhanced recovery.
production well
injection well
drive water
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CO2
water
CO2
oil bank
Three techniques are commonly used to extract petroleum and natural gas from Earth’s interior. Primary recovery relies on underground pressure to drive petroleum to the surface. If the pressure falls, pumps are used to bring petroleum to the surface. During secondary recovery, water is injected into the rock to bring petroleum to the surface. In enhanced recovery, such as thermal recovery, gas injection and chemical flooding are used to bring the remaining petroleum to the surface.
Predict What are some
methods used to extract petroleum and natural gas from the subsurface?
Petroleum and Natural Gas Extraction and the Environment Extracting fossil fuels, such as petroleum or natural gas, from Earth’s interior can affect air quality. Refining petroleum releases toxins into the atmosphere, and oil spills produce environmental hazards. FIGURE 6: Fossil fuels can be extracted from Earth’s interior by drilling horizontally as well as vertically into petroleum and natural gas reservoirs.
gas-saturated sandstone oil-saturated sandstone
gas reservoir
sandstone/shale shale
water-saturated sandstone (porous) shale limestone gas-bearing formation
However, advanced drilling processes can minimize the environmental impact of extracting petroleum from Earth’s interior. Horizontal drilling begins when a vertical hole is drilled into rock. Drilling is then turned horizontally to exploit a particular rock layer, which yields natural gas more readily and with fewer drill holes. During a process called multilateral drilling, the drill hole accesses multiple layers underground to more efficiently remove natural gas by using a single drill hole. Extended reach drilling is an advanced process that can cover great distances in the subsurface, which exceed traditional vertical drilling methods. Complex path drilling extracts petroleum and natural gas from a single drill well using several routes, which improves well efficiency.
Analyze How does horizontal drilling decrease the environmental impact of extracting oil and natural gas?
In addition to these drilling processes, other technological innovations such as D and D seismic imaging are also utilized. Advanced imaging improves exploration efficiency by reducing the number of drill holes, minimizing environmental impact.
Explain How have drilling technologies advanced to improve the efficiency of natural gas
and petroleum extraction from the subsurface? Lesson 3 Energy Resources
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EXPLORATION 2
Coal, Tar Sands, and Oil Shale The United States obtains 80% of its energy from fossil fuels. Although the extraction, processing, and use of fossil fuels contribute to the job market and the economy, there is a cost. The burning of fossil fuels causes long-term environmental damage by increasing greenhouse gases in the atmosphere, which elevates the average global temperature and reduces water quality. Pollution from fossil fuels can also be a health risk, and over-reliance on fossil fuels can potentially impact international relations and national security.
The Importance of Coal Predict How is coal used
in various energy outlets?
For centuries, coal has been used to generate energy. Today, coal—the largest domestically produced source of energy in the United States—generates about 50% of the country’s electricity. Approximately 900 million tons of coal were mined in 2015. The energy in coal is stored in the bonds of ancient plants that died millions of years ago. Coal is classified into three types: anthracite, bituminous, and lignite. These classifications are based on carbon content and rated from highest to lowest. Coal with the highest carbon content (anthracite) produces the most heat energy when burned.
World Coal Consumption, 2007
World Coal Consumption, 2007
Electricity generation Other uses Other industry Steel manufacturing Cement plants Heating
3%
FIGURE 7: The circle graph shows the percentages of uses for coal.
4% 7% 8%
10%
68%
Source: International Energy Agency, 2009
Coal Extraction Predict What are the differences and similarities between strip mining and open-pit coal mining?
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Surface mining processes to extract coal include strip mining, open-pit mining, and mountaintop removal mining. During these processes, the topsoil, vegetation, and rock are removed and placed to the side, which exposes the coal deposit at the surface. Strip mining is commonly conducted on fairly flat terrain in order to expose coal in long strips. Open-pit mines are large pits that are dug using heavy machinery to expose seams of coal. Mountaintop removal mining involves removing up to 1000 vertical feet of vegetation and rock from a mountain to expose the coal.
FIGURE 8: Coal is extracted from the surface using (a) mountaintop removal mining or from the subsurface using (b) longwall mining.
a Mountaintop removal coal mining
b Longwall mining
Image Credits: (l) ©Robb Kendrick/National Geographic Magazines/Getty Images; (r) ©Jacek_Sopotnicki/iStock/Getty Images Plus/Getty Images
Coal can also be mined underground. Room-and-pillar mining uses machines to dig into Earth’s surface. Large rooms are excavated along the coal seam. Some of the excess rock that is removed is used to support the room to prevent cave-ins. Coal is loaded onto shuttle cars, which transport the coal to the surface. Longwall mining uses mechanized shearers to cut pits into the earth. Long walls up to 600 feet wide are cut along the coal seam, allowing for up to 80% of coal removal. Temporary hydraulic roof supports are then used to hold up the roof during coal extraction.
Coal Mining and the Environment All three types of coal contain sulfur, which is a major source of environmental pollution. Coal mining also results in land disturbance, soil erosion, noise pollution, water pollution (acid mine drainage), and mine subsidence. Acid mine drainage is caused by the outflow of acidic water from coal mines.
Analyze What are some of the environmental consequences of coal mining?
Only with careful planning and implementation of pollution-control measures, monitoring, and reclamation can the negative impact of coal mining on the environment be minimized.
Problem Solving
Mountaintop Removal Coal Mining Mountaintop removal coal mining is a process for mining coal in which all or a portion of a mountain is removed so that one or more seams of coal may be extracted. The removal of the rock that makes up the mountain is accomplished with explosives, and the rock that is broken up is placed in adjacent valleys. This type of mining has generated controversy because of its effects on water quality and on the terrestrial environment. Water-quality problems include the degradation of streams from toxic chemicals and the potentially lethal consequences to organisms, such as fish and birds. Terrestrial impacts include forest loss and fragmentation, soil loss, loss of biodiversity, and negative health effects on humans.
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The Importance of Tar Sands and Oil Shale Gather Evidence How
do oil shale and tar sands differ from petroleum?
FIGURE 9: (a) Tar sands and (b) oil shale offer two reserves of fossil fuels that can be exploited as an energy resource.
Tar sands and oil shale offer new reserves of petroleum that have only recently become available through advances in drilling technologies. Tar sand contains bitumen, a thick, sticky substance that does not flow like petroleum. Tar sands can be mined and processed to extract the petroleum-rich bitumen, which is then refined into oil. Much of the world’s petroleum is found in the subsurface as tar sands. Tar sands are found in the United States, specifically in eastern Utah along public lands. Oil shale is a sedimentary rock that contains kerogen, a solid bituminous material. The kerogen formed millions of years ago when organic matter was deposited with finegrained sediment on lake and ocean floors. The kerogen that is locked in the rock is released as hydrocarbons when the rock is heated. The largest deposits of oil shale in the world are found in portions of Colorado, Utah, and Wyoming. This oil reserve is not readily accessible; the recovery of oil from oil shale comes at a relatively high cost. In addition, numerous regulations prevent the leasing of land for oil shale production.
Extracting Tar Sands and Oil Shale
b Oil shale outcrop
Because bitumen cannot be pumped from the ground like traditional petroleum reservoirs, it must be mined. Near-surface tar sands can be accessed by open-pit mining. Similar to mining for coal, open-pit mining for tar sands requires the removal of the topsoil, vegetation, and rock layers to expose the sticky tar sand layer. The tar sand is extracted and sent to an onsite facility. There the sticky sand is mixed with hot water and shaken to separate the bitumen from the sand. The bitumen floats to the surface. It is skimmed off and mixed with chemicals so it can be processed further. FIGURE 10: The process of recovering oil from tar sand requires steam injection (stage 1), followed by time for the steam to heat the viscous oil (stage 2). Once the oil has been heated, it, together with condensed steam, is pumped to the surface (stage 3).
stage stage 1
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stage stage 22
stage stage 33
Image Credits: (tl) ©francisblack/iStock/Getty Images Plus/Getty Images; (cl) ©Jonathan Blair/Corbis Documentary/Getty Images
a Hand sample of tar sands
Subsurface mining techniques include steam injection, solvent injection, and firefloods. During steam injection, two wells are drilled deep into the subsurface to reach the tar sand reservoir. Steam is then injected into one well to heat the sand and release the bitumen. The second well is used to bring the bitumen to the surface. Steam injection is the method most commonly used to extract bitumen from subsurface reservoirs. For solvent injection, two wells are drilled into the tar sand reservoir. A solvent is then mixed with the steam that is injected into one well, while the bitumen that is released is pumped to the surface through the second well. During firefloods, compressed air is injected into a well and partially burned to provide heat to reduce the viscosity of the bitumen, allowing it to flow in advance of the approaching fire toward the second well. The bitumen is then pumped to the surface. Hydraulic fracturing is a common practice employed to remove natural gas from the subsurface of Earth. During hydraulic fracturing, a well is drilled into the subsurface into a rock unit that potentially contains natural gas. However, the subsurface rock is not permeable, which makes it impossible to pump the gas out using normal practices. So, a steel pipe, called a casing, is inserted into the well. The pipe contains holes, and millions of gallons of water, sand, and chemicals are released through the pipe and pumped into Earth’s interior. These substances are injected into specific regions of the surrounding rock, causing it to break or fracture, releasing any gas that may be contained within the rock.
Explain What happens
during the process of hydraulic fracturing?
FIGURE 11: In hydraulic fracturing, fluid is injected into a well to produce pressure that cracks or fractures the rock. The fractures enable the extraction of petroleum and natural gas. (a) Gun charges blast holes through the well casing and the surrounding rock. (b) Sand, water, and chemicals are pumped in at high pressure to fracture the rock further. (c) Sand particles prop the cracks open. Gas escapes through the cracks and flows up to the surface.
water table water table
natural gas natural gas storage tanks storage tanks
a
b
c
Gun charges blast holes through the well casing and into the surrounding rock.
Sand, water and chemicals pumped in at high pressure further fracture the rock.
Gas escapes through fissures propped open by sand particles and up to the surface.
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Extracting Petroleum from Tar Sands and Oil Shale Mining tar sands and oil shale can have serious environmental consequences. The mining processes used to extract tar sands from the subsurface disrupt the surrounding landscape and ecosystems. One gallon of gasoline refined from tar sands produces more carbon dioxide than one gallon of gasoline produced from conventional petroleum. The extraction and refining processes require three times more water than conventional petroleum extraction processes do. Every gallon of gasoline produced from tar sands requires about six gallons of fresh water. Most of this water contains toxic chemicals that are harmful to human health and the environment. The environmental consequences of extracting oil shale from the subsurface parallel those for tar sands. The extraction process disturbs landscapes, negatively affecting the surrounding plants and animals. In addition, the extraction process requires large amounts of water. Refining oil shale is energy intensive and produces an estimated three times as many greenhouse gas emissions as refining petroleum does. Model How is petroleum
extracted from oil shales?
Similar to oil shale and tar sand extraction, hydraulic fracturing also affects the landscape and water quality. Many of the chemicals used during the fracturing process are toxic to people and animals. These chemicals have been shown to affect respiratory, gastrointestinal, nervous, immune, cardiovascular, and endocrine systems. It takes only a small amount of fracturing chemicals to contaminate watersheds, groundwater, and soil. The hydraulic fracturing chemicals also affect air quality, which can result in headaches, dizziness, insomnia, nausea, blurred vision, and even blindness. In addition, the disposal of hydraulic fracturing fluids, which contain heavy metals, radionuclides, organics, and brines used during the extraction process, poses a serious health risk.
Engineering
An Alternative to Hydraulic Fracturing A new process is now under development that involves using electric heaters placed in deep vertical holes that have been drilled through a section of oil shale. The oil shale is heated until it reaches a temperature between 345 °C and 370 °C (650 °F and 700 °F), at which point oil is released from the shale. The released oil is gathered in collection wells within the heated zone. A freeze zone of refrigerated fluid is established around the perimeter of the area to be mined so that no groundwater enters the perimeter and no hydrocarbons are released from the perimeter.
Explain What are the various techniques used to extract coal, bitumen (in tar sand), and
kerogen (in oil shale) from the subsurface? 154
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EXPLORATION 3
Solar and Wind Energy Many types of energy resources are continually replenished and never run out. These resources are called renewable resources. Most renewable energy comes directly from natural resources such as the sun, the wind, the tides, moving water, and Earth’s internal heat energy.
Active vs. Passive Solar Energy Systems Explain How is solar
The sun is the primary source of energy on planet Earth. In fact, the amount of energy Earth absorbs from the sun in one hour is more energy than is actually used by everyone on the planet in one year. Solar power is a renewable energy source derived from the sun that can be used to provide heat and electricity.
power used to heat homes?
FIGURE 12: Two solar heating systems ceilings are heavily insulated
energy from the sun heats water inside the solar collectors
vent allows hot air to escape in summer
insulated drapes or window shades reduce nighttime heat loss in winter
summer sun
shade trees help keep a home cool in the summer
winter sun
cold water from water supply is heated by water from solar collector
pump
a
thick walls and floors store heat in winter
hot water tank
An active solar heating system
south-facing, double-paned windows let sunlight in but reduce heat loss on cold nights
hot water for household use
b
A passive solar heating system
Active solar heating systems use solar energy to heat liquid or air. The energy from the sun is transferred to the fluid, which then carries it into a home or building. Passive solar heating takes advantage of a building’s location, landscaping, and building materials to minimize energy use. A passive solar building reduces heating and cooling loads through energy-efficient strategies, such as window orientation, which can affect how much heat enters the building.
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Analyze What are the
pros and cons of solar energy?
FIGURE 13: Many residents install solar voltaic technology on their homes to harness the power of the sun.
Photovoltaic Cells Photovoltaic technology is used to convert visible light into electrical energy. Photovoltaics are composed of cells, which are connected to form chains that boost power output. The power is amplified further when chains are aligned in arrays. One or more arrays are connected to the electrical grid, which completes the photovoltaic system. This energy is then transferred to residents. Many states that receive consistent sunlight, such as California or Nevada, have greatly benefited from solar power. Solar technologies offer clean energy that is available as long as the sun shines. This technology is easy to install. While the cost of solar technology is decreasing, it is not inexpensive. Some states offer tax credits to offset installation costs. In addition, excess energy that is generated from residential photovoltaic systems is returned to the electrical grid and offered as a credit to customers. The maintenance cost of photovoltaic systems is low compared to other systems. One of the greatest limitations of solar energy is the intermittency and unpredictability of solar energy during different seasons. In order to maintain a continuous supply of energy based solely on solar power, batteries are required to store the energy—this can also add to the cost of a solar energy system.
Solar Power Plants Hands-On Lab Solar Cooker Design and build
a solar cooker.
Analyze How do
photovoltaic systems compare to solar power plants?
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Solar power plants consist of a field of mirrors called heliostats that capture sunlight and heat a synthetic oil or salt, which is used to heat water. The water produces steam that turns a turbine to produce electricity that is transmitted by power lines to customers. While the installation of a solar power plant is expensive, it is far more economical than the installation of a new, cleaner, coal-fired power plant or nuclear power plant. In addition, solar power plants do not require additional fuels to operate, making them one of the cheapest power plants to run. Solar power costs as little as 1.14 cents per unit, compared to coal power that costs 4 cents per unit or nuclear power that costs 2 cents per unit. Like photovoltaic systems, the greatest drawback to solar power plants is when sunlight is limited. To sustain electricity, the power plants maintain a natural-gas boiler to ensure energy is available during cloudy days. Also, solar technology is still in its infancy, with maximum solar efficiency around 25%. FIGURE 14: The Crescent Dunes Solar Energy Plant located in Nevada Image Credits: (t) ©Smileus/Shutterstock; (b) ©Ethan Miller/Getty Images
Explore Online
Power from the Wind Earth’s surface is not a uniform temperature. The differential heating around the planet produces pockets of high pressure and low pressure. Air moves along these pressure gradients from high to low, producing wind. Wind is a renewable energy resource that will continue to blow as long as the sun shines. Wind turbines harvest wind energy. Wind turns the blades of a wind turbine, which is attached to an internal shaft that turns a generator and produces electricity. This electricity is funneled through a centralized substation, then transmitted to homes, businesses, and schools.
Explain How does a wind
turbine generate electricity?
FIGURE 15: Wind turns the blades of the turbine, which spins a shaft connected to an electric generator.
wind direction
generator
tower
power line
Farming the Wind
Image Credits: (b) ©philipbird123/Fotolia
Interest in harnessing the power of wind as an energy source originated in the 1970s around the same time the oil market fluctuated. Since then, the United States has made inroads into developing technologies to efficiently harvest wind power to generate electricity. The location of a wind farm is important because wind speed and duration must be fairly constant to be effective. Wind farms are often located on the top of smooth, rounded hills; on flat, open plains; along shorelines; or in mountain gaps where wind is funneled through a pass. Ideal conditions should produce a wind with a velocity of at least 23 km per hour (14 mph). Wind speeds that exceed this value can be dangerous for the windmills. When wind speed is too high, the windmill must be shut down to prevent damage. Most wind plants in the United States are privately owned. The wind-produced electricity is sold to the electric companies, where it is transmitted onto electrical grids and made available to the public.
Predict Where is the
best location to place a wind farm?
FIGURE 16: A wind farm
The biggest drawback of wind-produced electricity is a limitation in the current electrical grid system in the United States. The transmission lines in the current grid system are too small to carry the heavy loads of energy produced by wind farms over a long distance.
Analyze What are the benefits of a wind farm?
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EXPLORATION 4
Hydroelectric, Tidal, and Geothermal Energy Solar and wind are the two most common forms of renewable energy. However, there are other types of renewable energy that also can be beneficial. Hydroelectric energy converts the energy in moving water into electricity. Tidal energy also harnesses the energy of moving water—tides are more predictable than wind, and new technologies are being developed to harness this clean, renewable energy source. While the sun provides most of the heat to the planet’s surface, Earth’s interior (geothermal heat) also produces geothermal energy that can be converted to electricity.
Hydroelectric Power Technology The potential energy of moving water is powerful. Water can erode sediment, scour landforms, and is mighty enough to produce electricity. The energy produced by moving water is called hydroelectric power. Similar to windmills, moving water pushes turbines that power electrical generators. The generators convert the energy into electricity. Hydroelectric power accounts for about 7% of the total energy production in the United States. Idaho, Washington, and Oregon use hydroelectricity as their main power source. FIGURE 17: Hydroelectric power plants use moving water to run turbines. (a) The water supply flows down a channel (the penstock) from the reservoir. (b) Flowing water turns the turbine, which then turns the generator that generates electricity. (c) Water is discharged into a river or stream.
reservoir
dam
generator
sluice gates a b
power lines penstock
c turbine
discharge pipe river or stream Explain How is the
energy in moving water converted into electricity?
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To produce hydroelectric power, a dam is built on a large river that has a significant drop in elevation. The dam stores water behind it in a reservoir. Near the bottom of the dam wall, water flows through a water intake. Gravity causes the water to fall through the penstock, a channel for conveying water to a waterwheel or turbine inside the dam. At the end of the penstock, moving water is forced through a turbine propeller. The shaft of the turbine is attached to the generator, which produces the electricity. Power lines are connected to the generator.
Pros and Cons of Hydroelectric Power Hydroelectric power is beneficial because it is a clean, renewable energy resource that does not pollute the air, water, or land. Hydroelectric power is one of the cheapest and most efficient methods of producing electricity, and it can easily and rapidly meet peak demands for electricity in a region. In addition, hydroelectric power plants, once built, have fairly low operating costs.
Analyze How does
construction of a dam affect the surrounding landscape and ecosystems?
FIGURE 18: Hydroelectric power and the environment
a
A fish ladder provides a way for migrating fish to move around obstacles like dams.
b
This lake in the Khao Sok National Park in Thailand was created after a dam was built.
However, building a dam to produce hydroelectric power has its drawbacks. The construction of a dam is very expensive. A dam can affect the surrounding environment by altering the landscape and preventing the normal flow of a river. A dam can also affect water quality and interfere with the migration of organisms upstream in a river. Additionally, dams can flood large areas of land.
Image Credits: (tl) ©imfotograf/Fotolia; (tr) ©CHROMORANGE/Ewa Jermakowicz/Alamy
Tidal Power Technology Tidal stream power plants harness the energy produced in the tides. These systems work on the principle of kinetic energy produced by flowing water. As the tide rises, Gate closes water enters a bay behind a dam. The gate then closes at high tide. The gate opens at low tide, and the water in the bay rushes through, turning a turbine that generates electricity. Tidal power is only limited by the number of available sites where tidal barriers can be placed.
Explain How is tidal barrier electricity similar to hydroelectric power?
high tide
FIGURE 19: Tidal barriers are constructed along a coastline with a large tidal range to take advantage of the power in moving water.
Gate closes
Gate opens
high tide high tide
Gate opens
low tide
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The Pros and Cons of Tidal Power Predict What are the
pros and cons of geothermal energy?
Tidal energy is a clean, renewable energy resource. It requires no fuel, so it is emission free. Tidal power is highly efficient and has a predictable output. In addition, tidal barriers can double as storm-surge barriers. Unfortunately, a tidal barrage plant is very costly to build and maintain. In fact, only a few plants are actually operating around the world. The placement of a tidal barrage plant requires a coastal area with an extreme range of high and low tides. The plants also have a profound, often negative, effect on the surrounding environment. Tidal power stations can decrease the salinity of tidal basins and can kill marine life. FIGURE 20: The Sihwa Lake Tidal Power Station in South Korea was completed in 2011 at a cost of $355 million. The facility uses 10 submerged turbines.
Explain What is geothermal energy?
Geothermal energy is energy derived from the heat of Earth. Geothermal energy can be tapped in areas of volcanic activity, as well as in geysers and hot springs, and can be recovered in several ways. The first is by direct use, where hot water from the subsurface is used to heat buildings. This process is used for buildings in Iceland. The second process used to tap geothermal energy is by the use of geothermal heat pumps. Air or antifreeze is pumped through pipes buried in the subsurface and the heated fluid is circulated through a building. A geothermal power plant uses steam produced from superheated water in Earth’s interior to rotate a turbine. The turbine activates a generator to produce electricity. The United States is a global leader in installed geothermal capacity. Eighty percent of this capacity is located in California, where more than 40 geothermal plants provide nearly 7% of the state’s electricity. In 2015, United States geothermal power plants accounted for 0.4% of the country’s energy needs.
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Image Credits: ©Yonhap News/YNA/NewsCom
Geothermal Power Technology
FIGURE 21: Geothermal power plants generate electricity according to the following process: (a) steam rises through a well; (b) steam drives turbines, which generate electricity; (c) leftover liquid water is pumped back into the hot rock.
bb
cc aa
hot hotrockrock
heated water heated water
The Pros and Cons of Geothermal Power
Explore Online
Hands-On Lab Geothermal energy is a clean, renewable resource powered by the natural radioactive OR ID it is virtually unlimited decay of elements in Earth’s interior. Unlike wind and solar, and can be used to heat and cool buildings. Geothermal energy requires no fuel and UT The drawbacks to is almost emission free, and it produces a low carbon footprint. NE geothermal energy are the limited locations where it can be accessed; a minimum temperature of 175 °C (350 °F) is required CA in the subsurface to generate electricity. Long-distance transmission tends to be inefficient and results in significant losses. Geothermal power also uses a large amount of water, and construction of power plants is costly. AZ OR
PACIFIC OCEAN
ID
UT NE
Favorability for geothermal power Most favorable
Generation of Natural Gas from Biomass Build a waste
material digester to produce and gather methane gas. Research how methane is used in industry.
FIGURE 22: California and Nevada have many locations that can be utilized for geothermal energy.
CA
Least favorable Not favorable AZ
PACIFIC OCEAN
Geothermal power station
Favorability for geothermal power Most favorable Predict What are the pros and cons of geothermal energy?
Least favorable Not favorable Explain How does geothermal energy, hydroelectric energy, and tidal energy compare Geothermal power to solar or wind energy? station
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CONTINUE YOUR EXPLORATION
Guided Research Harnessing the Power of the Sun
Engineers are working to build bigger and better solar power plants. Someday, active solar power could replace coal or nuclear power. However, presently, the development of the complex systems needed to efficiently harness solar power and produce enough electricity to meet global demands is very expensive and may take decades to complete. Passive solar heating offers a low-tech, less expensive approach to solar energy and may be better suited for immediate use. Traditionally, a passive solar heating system includes a thermal mass that stores heat, such as a thick concrete wall or barrels of water. These materials, however, are bulky, take up space, and may soon be obsolete. Researchers are testing thermal-mass materials that are up to 14 times more efficient at storing and transferring heat. These materials have been used to make a new product called a phasechange wallboard. A phase change occurs when the state, or phase, of matter—solid, liquid, or gas—changes. Researchers have incorporated materials, such as paraffin wax, into normal gypsum drywall. When the outside temperature rises, the material in the wallboard slowly melts but remains at a constant temperature
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FIGURE 23: This sunken house, built in the Chiltern Hills of England, has grass planted on the roof and the largest sliding glass doors in the world.
until it is entirely melted. It absorbs the sun’s energy without getting hotter. At night, when the air outside cools, the material radiates heat while returning to its solid state. Phase-change wallboard can keep temperatures inside a building comfortable in the summer and in winter. Widespread use of this product would significantly reduce the demand for coal and nuclear energy. Simulations in Dallas, Texas, indicate that the use of phase-change wallboard could shift as much as 90% of the air conditioning to off-peak hours. Parts of California might even be able to eliminate air conditioning altogether by using this material. Analyze How can a simple
change to a common building material help to reduce the demand for electricity?
OIL WELL
Language Arts Connection
Brainstorm a plan to simulate a model of phase-change solar-energy technology. Your simulation should include the following concepts, and you should explain how they are modeled in a written report. The simulation can be in the form of a computer model, a video, a mathematical model, a conceptual model, or a hands-on activity. • The simulation should model a costsaving technological approach to solar energy. • The technology can be an improvement on traditional passive solar heating and cooling using phase-change materials. • The phase-change material may be applied to walls, windows, ceilings, flooring, or attic insulation.
Go online to choose one of these other paths.
Image Credits: ©Will Pryce/Arcaid Images/Alamy
Is active solar power the only “real” solar power? Can passive solar technology also help to conserve Earth’s fossil fuels and protect our environment? Researchers are investigating many ways to utilize the sun’s energy.
EVALUATE
Lesson Self-Check CAN YOU EXPLAIN IT? FIGURE 24: A station that uses hydraulic fracturing to obtain natural gas
Image Credits: ©Yarygin/Shutterstock
Both renewable and nonrenewable energy resources have both advantages and disadvantages in terms of their extraction and use. For instance, hydraulic fracturing is a method now used to extract natural gas from a specific rock unit in the subsurface. The rock that makes up the subsurface rock unit is impermeable, which means it is impossible to remove natural gas from the rock using conventional drilling methods. Instead, a steel pipe or casing is inserted into the well. This pipe contains a series of holes. A tremendous amount of water, sand, and chemicals is pumped through the pipe into the area of the subsurface where gas is contained in the rock. These substances are injected through the pipe into the rock, causing the rock to fracture and releasing petroleum and natural gas in the process. Therefore, the major benefit of hydraulic fracturing is that it allows access to natural gas in a way that is not available through traditional drilling. This will allow countries such as the United States to reduce their dependency on foreign petroleum sources. In addition, hydraulic fracturing is creating more new jobs.
Analyze What environmental implications are associated with hydraulic fracturing to obtain petroleum and natural gas from the subsurface?
Some disadvantages of hydraulic fracturing involve the chemicals used in the process. These chemicals can be toxic to both people and animals. They can also contaminate watersheds, groundwater, and soil. Because hydraulic fracturing uses so much water, it may also lead to a decrease in water supplies. Explain Refer to the notes in your Evidence Notebook to explain the technology
used in the hydraulic fracturing method of extracting petroleum and natural gas from oil shale.
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EVALUATE
CHECKPOINTS Check Your Understanding 1. What characteristic makes an energy resource renewable?
9. What are the top three fossil fuels used for energy production in order from most used to least used? a. coal, petroleum, natural gas b. coal, wood, petroleum
a. It formed millions of years ago.
c. natural gas, wood, coal
b. It comes from nature.
d. petroleum, coal, natural gas
c. It is replenished every day. d. It does not pollute the environment. 2. Which technique is used to recover natural gas from the subsurface? a. Open-pit mines are dug. b. A vertical hole is drilled. c. Room-and-pillar mining is used. d. Longwall mining is used. 3. What additional step is required to recover bitumen from tar sands in the subsurface? a. Open-pit mines are dug. b. The resource is heated with steam or liberated with solvent. c. The bitumen is diluted before refining. d. Lateral drilling is performed. 4. How do new drilling methods for petroleum improve fossil fuel extraction efficiency and reduce the impact on the environment? 5. What technology is used to obtain energy from renewable resources? Choose all that apply. a. photovoltaic cells b. synthetic oil c. wind moving blades d. D models
10. Why might Las Vegas, Nevada, benefit from solar energy more than Portland, Oregon? 11. What factors might a community consider if it wanted to build a windmill farm in the area to offset energy needs with clean, renewable energy? 12. Which of the following substances is used to bring petroleum to the surface during secondary recovery? a. CO2 b. water c. steam d. solvent 13. Which of the following is a benefit of building a hydrothermal electric plant? a. Hydroelectric plants do not have to placed at specific locations. b. Hydroelectric plants are powered by the natural radioactive decay of elements. c. Hydroelectric plants can be used as storm-surge barriers. d. Hydrothermal electric plants have fairly low operating costs. 14. The world’s largest source of oil shale is located in which of the following countries? a. Canada b. United States
6. Compare the pros and cons of using different renewable energy resources. 7. How might life be affected if all fossil fuels were no longer available? 8. Explain the process by which energy from tides is used to produce electricity.
c. China d. Mexico 15. Which of the following is the biggest drawback to the use of wind energy in the United States? a. Transmission lines are too small to carry heavy loads. b. Very few locations have adequate wind velocity. c. Most wind farms are privately owned. d. Wind-produced energy is sold to electric companies.
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16. Hydraulic fracturing is a method used to bring which of the following resources to Earth’s surface? Choose all that apply.
22. Which of the following nonrenewable energy resources are used primarily for the generation of electricity? Choose all that apply.
a. petroleum
a. coal
b. bitumen
b. petroleum
c. natural gas
c. nuclear energy
d. kerogen
d. natural gas
17. Which of the following renewable energy resources are dependent on location for their success? Choose all that apply. a. hydroelectric energy
23. Explain how solar power plants produce electricity. 24. Describe the process by which petroleum is extracted from tar sands.
b. solar energy c. wind energy d. geothermal energy 18. Which of the following components are necessary to produce petroleum and natural gas reservoirs? Choose all that apply. a. water b. heat c. a permeable layer
25. Describe some of the environmental problems that can potentially be caused by the use of hydraulic fracturing. 26. Explain where wind farms must be located to capture a sufficient wind velocity to help generate electricity. 27. Explain why states like California and Nevada are good locations to construct geothermal energy plants. 28. Describe the process of longwall coal mining.
d. an impermeable layer 19. Which of the following statements are true about a passive solar energy system? Choose all that apply.
29. Explain how mountaintop removal coal mining is different from open-pit coal mining.
a. It uses solar energy to heat liquid or air. b. It takes advantage of a building’s location, landscape, and building materials to minimize energy use. c. It reduces heating and cooling loads through energy-efficient strategies. d. It transfers energy from the sun to a fluid, where it is then carried into a home or building. 20. The most important use of petroleum is to produce a. diesel fuel and heating oil. b. jet fuel. c. asphalt. d. gasoline.
MAKE YOUR OWN STUDY GUIDE In your Evidence Notebook, design a study guide that supports the main ideas in this lesson: Remember to include the following information in your study guide: • Use examples that model main ideas. • Record explanations for the phenomena you investigated. • Use evidence to support your explanations. Your support can include drawings, data, graphs, laboratory conclusions, and other evidence recorded throughout the lesson.
21. Which of the following is the most important use of coal? a. electricity generation b. steel manufacturing c. heating d. cement production
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A BOOK EXPLAINING COMPLEX IDEAS USING ONLY THE 1 000 MOST COMMON WORDS
STUFF IN THE EARTH WE CAN BURN How we get things we need out of the ground You’ve explored rock, mineral, and energy resources that are essential to life on Earth. What methods have humans devised to find and extract those valuable resources from deep inside Earth?
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RANDALL MUNR OE XKCD.COM
HOW WE GET BLACK ROCKS OUT OF THE GROUND If the rocks aren’t very deep, we can make holes under the ground and carry them up with machines. This is how we used to get most of the rocks we burned.
As we built bigger earthmoving machines, we learned to just move all the trees and land out of the way to get the rocks.
Some rocks are inside mountains, so some companies have started blowing up the tops of the mountains so they can get the rocks out more easily.
HOW WE GET FIRE WATER AND FIRE AIR OUT OF THE GROUND
FIRE AIR FIRE WATER
We make holes looking for places where lots of things died. When we fi nd a pool, we push a stick down and pull up all the fire air and fire water.
Over time, some dead things slowly turn to fire water and fire air. These are both lighter than rocks and rise up through tiny holes. When they reach a rock with no holes, they form pools, with the lighter air on top.
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STUFF IN THE EARTH WE CAN BURN This kind of work leaves pools full of heavy metals and strange kinds of water that was used to get the black rocks out. Sometimes you can notice the bright colors of these pools from the air. When companies are done making holes, they often leave the pools behind. People worry about whether the stuff in the pools could be bad for us. Sometimes birds land in the pools and die.
BLACK ROCKS
HOLES
One reason we make holes that bend is so we can reach under cities without bothering people.
HOW DEEP? We can only get black rocks easily if they’re not too deep in the ground. The biggest problem is that deeper in Earth, rocks are hotter. It’s hard to get a lot of rock up out of the ground, and if the rocks are too hot, that makes everything so hard that it’s not worth it. There are other problems. You need to cut big rooms into the ground to get black rocks out, and it’s hard to hold the roof up when there’s so much rock piled up on it. Sometimes the roof falls, and people die.
Layers of rock from different times
STRANGE SHAPE When a sea dries up, it leaves lots of this white stuff behind. Sometimes, the stuff gets covered in dirt and sand. When the layers above the white stuff get heavier, it can make the white stuff start to rise up and push through the layers above. It looks like paint drops falling from a ceiling but going up.
ROCK BREAKING Big, easy-to-reach pools of fire water are getting harder to fi nd, so we’ve been trying new ideas for getting it from the ground. We’ve found that sometimes, rock has fire water or air you can burn stuck in it. To get it out, we push water into the ground so hard that it makes the rocks break. Then we push in small rocks or glass to hold the breaks open, and the fire water and fire air come out through the openings. Making all these holes in the rock might mean that when we drink water, we’ll also drink whatever stuff they use to get fire water out, since everything can run through the new holes in the rock. 168
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WHITE STUFF This is white stuff, like what we put on food to make it better (although we mostly get the kind we eat from drying out seawater). We make holes like this to get white stuff out, then we put it on our roads to get rid of snow and ice. We sometimes use the spaces we leave behind to hold stuff, like fire water or fire air that we want to save to burn later.
Go online for more about Thing Explainer.
HOLES
FIRE WATER
Places where the ground broke DEEP POOLS We can get fire water and fire air from much deeper places than we can get black rocks. Since it forms pools and can run through small holes easily, we only need to make a very thin hole to get it out instead of having to move all the rocks around it.
© num_skyman/Shutterstock
FIRE WATER
FIRE AIR (on top of the fire water)
VERY DEEP HOLES
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UNIT CONNECTIONS
Mining Asteroids As the human population increases and as new technologies like electronics are developed and improved, the demand for rare elements is increasing. Meanwhile, the supply of mineral resources is decreasing. There is only so much that can be mined from Earth’s crust. One possible solution to this supply problem is to mine asteroids. Certain types of asteroids are rich in important and rare elements like nickel, gold, platinum, and rhodium.
FIGURE 2: Scientists estimate that the asteroid 16 Psyche contains more than 19 1.7 × 10 kg of nickel-iron. This is an illustration of a future NASA mission to explore 16 Psyche.
Use library and Internet resources to research plans for mining asteroids. What are some engineering challenges that need to be overcome to successfully mine asteroids? What are the safety and environmental risks? What are the potential benefits? Prepare a brief report describing the potential risks and benefits for someone who is thinking about investing in an asteroid mining project.
Social Studies Connection Exploration, Colonialism, and Natural Resources Human civilization has been shaped by people’s relationship with natural resources. The need and desire for mineral and energy resources such as gold, silver, tin, oil, and gas have fueled exploration and settlement of different parts of the globe as well as colonialism— the practice of invading and controlling another territory to exploit its resources.
FIGURE 3: In the mid-1800s, the quest for gold drew tens of thousands of settlers to California from around the world.
Use library or Internet resources to research the relationship between natural resources and exploration, expansion of a country, or colonialism. Choose a specific time and place in history such as the Gold Rush in the United States, the search for gold and silver in South and Central America, or more recent activity related to oil and gas exploration. Present your findings in one of the following forms: a) a map showing the locations of the resources and the routes that people traveled; b) a timeline of events; or c) a brief essay about the causes and effects of the exploration or invasion.
Environmental Science Connection Environmental Law Companies that mine for rock and mineral resources or drill for oil and gas must comply with certain laws that are designed to protect the environment. These laws differ from state to state within the United States, and they differ from country to country.
Use library and Internet resources to research the environmental laws that affect mining, drilling, or processing of natural resources in your area or another area of your choice. How do these laws affect the companies that own the mines or drilling operations, the workers, the local environment, and the people who live in the region? Choose a specific law, and write a brief report that explains the law. Describe the benefits and the costs or drawbacks of the law to the environment and to people, such as company owners, workers, residents, and consumers.
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FIGURE 4: The Clean Air Act was first passed in 1963 to control air pollution.
Image Credits: (t) ©JPL-Caltech/NASA Jet Propulsion Laboratory; (c) ©Clipper Ship Poster, 1849 (print), American School, (19th century)/Private Collection/Peter Newark American Pictures/Bridgeman Images; (b) ©snaphappy28/Fotolia
Engineering Connection
UNIT PRACTICE AND REVIEW
SYNTHESIZE THE UNIT
In your Evidence Notebook, create a concept map, graphic organizer, or outline using the Study Guides you created for each lesson in this unit. Be sure to use evidence to support your claims.
DRIVING QUESTIONS Look back to the Driving Questions from the opening section of this unit. In your Evidence Notebook, review and revise your previous answers to those questions. Use the evidence you gathered and other observations you made throughout the unit to support your claims.
When synthesizing individual information, remember to follow these general steps: • Find the central idea of each piece of information. • Think about the relationships among the central ideas. • Combine the ideas to come up with a new understanding. Go online to access detailed lesson summaries for this unit.
PRACTICE AND REVIEW Use the following scenario to answer Questions 1 through 4. Black smoker chimneys are structures made of minerals that form around hot springs on the ocean floor, more than 2 km below the surface. Rare organisms live on and around the chimneys. A natural history museum wants to collect some black smoker chimneys for a new exhibit hall. They also want to better understand chimney ecosystems and how the chimneys form. Before setting off on the expedition, a team of biologists, chemists, geologists, and engineers gets together to plan how to cut the chimneys down and bring them up to the surface and back to the museum without damaging them and with minimal damage to the ecosystem. They ultimately decide to place a metal cage and ropes around each chimney, use an underwater chain saw to cut it down, and then use a long rope to pull it up to the surface. 1. Which question best conveys the engineering problem that needs to be solved? a. How do black smoker chimneys form? b. Can organisms that live around black smokers also live on the surface? c. How can we collect a black smoker chimney from the seafloor without damaging it? d. What is the temperature and pressure of the water that comes out of the black smoker chimneys?
2. The museum has 24 months and $2 million to plan and complete the project. They will have six full weeks of ship time to study the ecosystem and bring back the chimneys. These are all examples of a. Criteria b. Tradeoffs c. Problems d. Constraints 3. Indicate whether each activity below is an example of (a) modeling, (b) ranking criteria, (c) troubleshooting, or (d) evaluating tradeoffs. a. The team decides to spend the last day gathering more data about the seafloor instead of trying to bring up another chimney. b. The scientists discuss which is more important: collecting a chimney that is still growing or collecting a chimney that is no longer growing. c. The engineers calculate the weight of the chimney in water and then use that information to figure out how strong the rope used to pull the chimneys up must be. d. A piece of the first chimney breaks off on the way up to the surface. The engineers decide to secure the second chimney with more loops of rope.
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UNIT PRACTICE AND REVIEW 4. Which is most likely to be true? a. The biologists, chemists, and geologists will agree on what part of the system is most important to study. b. Scientists and engineers on future expeditions to collect black smoker chimneys will use the design as a starting point. c. If the engineers are competent, the design for bringing up the chimneys will work well on the first try without any modification. d. If the scientists and engineers work hard enough, they will be able to meet all of the design criteria perfectly while working within all of their constraints. 5. A woman is trying to choose a new coat to buy. She can’t decide between a sheepskin coat or a synthetic fleece coat. She wants to choose the coat that causes the least damage to the environment. How can she use life cycle analysis to help make this decision?
9. Evaluate the following statement: All forms of mining and drilling have costs and risks as well as benefits. The development of new technologies can change the balance of costs and risks to benefits. Do you agree or disagree with this statement? Use evidence and reasoning to support your answer. 10. A country passes a law to reduce its reliance on nonrenewable resources that are accessed through drilling and mining. Which of the following energy resources is it most likely to invest in? Choose all correct answers. a. Bitumen b. Coal c. Hydroelectric d. Natural gas e. Petroleum f. Solar g. Tidal
6. The availability and use of natural resources has affected the development of human society. Which of the following statements are true? Select all correct responses. a. Native elements like gold and copper were used before alloys like bronze. b. Humans could not use rock and mineral resources until fire was discovered. c. The first known use of rock and mineral resources was in sculpture and other artwork. d. Native Americans were not concerned with the physical properties of rocks and minerals. e. The need for rock, mineral, and energy resources has driven human exploration and settlement. f. The types of resources that early humans used depended on what was available nearby or through trade. 7. Why are minerals that are rich in rare earth elements considered to be “critical and strategic”? 8. What factors must a mining company take into account when deciding what method to use to mine for a particular resource? Identify at least three factors, and briefly explain how each affects the decision.
h. Wind 11. Compare the costs and benefits of one type of fossil fuel with the costs and benefits of a renewable energy resource. 12. Describe the process that an engineering team might go through to design a way to reduce the environmental impact of extracting petroleum or natural gas.
UNIT PROJECT Return to your unit project. Finalize your proposal so that it clearly explains how the current recycling system works, how well it serves your community, how it needs to be improved, and what the benefits of improving the system will be to the community and to the environment. Remember these tips while you are finalizing your proposal: • Is the way the system works now clearly described? • Are the problems with the current system clearly identified? • Is the evidence and reasoning for improving the system clear? • Are the costs and benefits of your improved system clearly outlined? • Did you include an action plan?
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UNIT PERFORMANCE TASK
Carbon Fiber Solutions If you compare modern sporting equipment to equipment that was made decades ago, you’ll notice some differences. As new resources are discovered, new technologies and processes for mining and processing minerals are invented, and new materials are developed, engineers have replaced certain materials with others that are less expensive or have properties better suited for their function. One of the most popular new materials is carbon fiber.
FIGURE 5:
Carbon fiber road bike
1. DEFINE THE PROBLEM With your group, choose a type of sporting equipment that could be made using carbon fiber: for example, bicycles, rackets, bats, skis, snowboards, or skateboards. Brainstorm the criteria that the particular piece of equipment needs to meet. Think about its purpose, how it is used by athletes, and what qualities make one design or brand better than another. 2. CONDUCT RESEARCH On your own, conduct additional research into the properties of carbon fiber and the ways carbon fiber can be used in the sporting equipment you chose. Try to find out: What materials does carbon fiber replace? What are some important physical and chemical properties of carbon fiber? How much does carbon fiber cost relative to the materials it replaces? Where does carbon fiber come from? What are the possible environmental costs of using carbon fiber instead of more traditional materials? What are some other advantages and disadvantages of making this sporting equipment out of carbon fiber?
Image Credits: ©John Burke/The Image Bank/Getty Images
3. ANALYZE DATA Get back together with your team to discuss your findings. Analyze the benefits and costs of using carbon fiber in the sporting equipment. Make a chart that compares equipment made using carbon fiber to equipment made without it. Include how well the equipment performs, the price of the equipment, and the environmental cost or risks of using carbon fibers versus using other materials. 4.EVALUATE THE SOLUTION Do the benefits of using carbon fiber outweigh the costs? On your own, think about your personal priorities when it comes to buying sporting equipment. Which would you buy: the
equipment made with carbon fiber or with some other set of materials? Be prepared to explain your reasoning to the group. 5. C O M M U N I C A T E Get back together with your group and share your thinking. Did everyone come to the same conclusion? Why or why not? Discuss what factors went into each person’s thinking and how people weigh factors differently.
CHECK YOUR WORK Once you have completed this task, you should have the following: • A description of a piece of sporting equipment and the criteria that it needs to meet • A brief description of the important properties of carbon fiber and how it is used • A matrix comparing the costs and benefits of a piece of sporting equipment made with carbon fiber to one made with other materials • Your personal assessment of whether it is better to buy the equipment made with carbon fiber or with some other materials, supported by your reasoning
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