Human Dependence on Natural Resources

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1 You use Earth s resources every day. When you eat cereal with milk for breakfast, you use resources from plants and animals. When you ride the bus to school, you use energy (fuel) resources. When you take a drink of lemonade or iced tea, you use water resources. A resource is anything on Earth that humans use. We can use some kinds of resources over and over. Other kinds of resources can run out. What are some examples of resources on Earth? What might happen if they run out? How can we keep them from running out? What are renewable resources? Renewable resources can be replaced by natural processes within a lifetime. Some renewable resources, such as plants and animals, provide food for humans. Other renewable resources, such as sunlight and wind, provide energy. What are some more of our renewable resources? Sunlight (solar energy): Sunlight is a renewable resource. The sun will continue to shine for millions of years. We can use energy from the sun in many important ways. Solar panels capture sunlight and turn it into electricity. Humans use this electricity to power their homes and businesses. Air (wind energy): Wind can be used to create electricity too. Large windmills called turbines spin in fast-moving wind. The movement of the turbines blades creates electricity. Water (hydropower): Humans cannot survive without fresh water. The fresh water we use is replaced by the water cycle. Water is also a source of energy. Dams along rivers can use moving water to create electricity. The movement of water during tides can also provide energy. Hot water underground (geothermal) can also be used as an energy source Plants and animals (biosphere): Plants provide food, energy, and useful products for humans. For example, trees provide wood. Wood can be burned to heat a home. Wood can also be turned into paper or lumber. Plants such as corn, strawberries, and carrots provide food for many animals, including humans. Animals such as fish and cows also provide food. Some plant and animal products, such as corn and animal waste, can be converted to fuel. 1

2 What are nonrenewable resources? Nonrenewable resources are limited, and natural processes cannot replace them in a human lifetime. These resources take a very long time to form, yet we use these resources too quickly. Many rocks and minerals that we mine from Earth (for example, metals such as aluminum and iron) are also nonrenewable resources. Three kinds of nonrenewable resources that are fossil fuels are coal, oil, and natural gas, because they form from organisms that died millions of years ago (such as fossils). Coal: Coal is a solid material formed from swamp plants that died millions of years ago. Thick layers of rocks and soil covered the dead plants. The pressure of the rocks and soil turned the plants into a solid called coal. Humans dig coal out of the ground. Burning coal releases its energy. We can use this energy to produce electricity. These machines, called pump Oil: Oil is a liquid fuel formed from tiny marine animals jacks, pull oil up from deep under that died in the ocean millions of years ago. Layers of Earth s surface. mud pressed down on the dead animals. The pressure from the mud turned the dead animals into a liquid called oil. Oil can be turned into gasoline and other kinds of fuels. Oil is also used to make products such as plastics, DVDs, and tires. Natural gas: Natural gas forms the same way as oil. Over millions of years, tiny dead animals are pressed down by mud and rocks. The pressure forms tiny bubbles of gas. Natural gas has no smell, so scientists add a chemical to it to make it smell like rotten eggs. This way, when there is a gas leak, people know and can get to safety and call the gas company for help. Natural gas is used to heat homes and cook food. Rocks and minerals: Rocks and mineral ores can take millions of years to form. Concrete sidewalks are made of small pieces of rock cemented together. People use clay to make bricks. Sand is used to make glass. Diamonds and other gems are minerals. Marble and granite are rocks that people use for buildings and statues. Underground water: Water that is stored in aquifers (water trapped between layers of rock) is not renewable and should be conserved when we sink wells into these unique reservoirs of water. 2

3 Look at the two photographs below. Are these examples of renewable or nonrenewable resources? Write in the space below the photographs, explaining your answer. The uneven distribution of Earth s mineral, energy, and groundwater resources is the result of past and current geologic processes. These resources are typically limited and nonrenewable, due to the long amounts of time required for the resources to form or because the environments in which the resources were created occurred only once or very rarely in Earth s history. How can we conserve renewable and nonrenewable resources? Nonrenewable resources cannot be replaced in your lifetime. If we use all the coal, oil, and natural gas on Earth, there will be none left. It will take millions of years to replace these resources. How can we conserve, or save, nonrenewable resources? One solution to this problem is to use less coal, oil, and natural gas. There are many ways you can use less of our nonrenewable resources. For example, you can use public transportation instead of driving a car (fewer vehicles using gasoline), turn the lights off when you leave a room, and use fabric bags instead of plastic bags at the grocery store. 3

4 Renewable resources also must be conserved. For example, trees can be used to make fuel, paper, and lumber. But what happens if you cut down all the trees in a forest? It might take many years for all the trees to grow back. Humans should use some, but not all, of the renewable resources in an area, and we should replace the resources we use as quickly as possible. For example, we can plant new trees to replace trees that are cut down. Using some resources can hurt the environment. Oil spills in the ocean can hurt or kill the animals living there. Burning coal releases gases and smoke into the atmosphere that can harm living things. Animal farms can create waste that drains into rivers and pollutes them. One way to stop hurting the environment is to use fewer of these resources or find other ways to get energy. We can also use renewable resources, such as sunlight and wind power. These sources of energy create less pollution. Some products, such as gasoline or plastics, are made in special refineries or factories. You might think that these resources are human made and, therefore, do not come from Earth, but all resources can be traced back to some natural material that came from Earth. Gasoline and plastics are made from oil. Oil is a nonrenewable resource that comes from Earth. In honor of the first Earth Day in 1970, the Container Corporation of America held a competition for the best logo design to go on the recycled-paperboard products they were producing. Gary Anderson, a student at the University of Southern California, won the competition. This symbol is now recognized worldwide. Human dependence on Earth s resources creates problems. What do you think are the the limitations in using those resources? The conditions that formed the resources are specific to certain areas and times on Earth. When resources are used, they are depleted until they can be replenished, mainly through geologic processes. Because many resources (for example, minerals, fossil fuels) continue to take much longer than a human lifetime to form, these resources are limited to current and near-future generations. Some resources (for example, groundwater) can be replenished on human timescales but have limited distribution. Lastly, the extraction and use of resources by humans decreases the amounts of these resources available in some locations and changes the overall distribution of these resources on Earth. 4

5 Sunlight is an example of a renewable resource. Solar panels can convert sunlight into electrical energy. To do this, solar panels need to collect as much sunlight as possible. Try this short activity to learn more about solar panel design. You will need water, two foil pie tins, black construction paper, and two thermometers Cut a piece of black construction paper to fit into one of the pie tins. Place the construction paper at the bottom of the pie tin. Leave the other pie tin as it is. Pour the same amount of water into each pie tin. Record the temperature of the water in each pie tin. Put both pie tins in direct sunlight. Leave them in the sunlight for 20 minutes. After 20 minutes, record the temperature of the water in each pie tin. In which pie tin did the temperature rise the most? What does this tell you about how sunlight reacts with dark colors? If you were designing a solar panel, what color would you make it? This house gets some of its energy from solar panels on its roof. The panels convert sunlight into electricity. 5

6 Use what you know about renewable and nonrenewable resources to fill out the table below. First decide if you agree or disagree with the statement in the left column. Then explain why you agree or disagree in the right column. or? Explanation Renewable resources cannot be replaced in our lifetime. Solar power, natural gas, and wood are all nonrenewable energy sources. Both renewable and nonrenewable resources should be conserved. Nonrenewable resources exist in a fixed amount and can only be replaced by processes that take millions of years. Overpopulation and increased demand on the water supply, lack of water conservation practices, and pollution of water sources can cause water to become scarce. 6