Unit 10

1. Unit 10 Section 3: Natural Resources

2. Imagine…

4. What You Will Learn • Describe how humans use natural resources. • Compare renewable resources with nonrenewable resources. • Explain three ways that humans can conserve natural resources.

5. What does the water you drink, the paper you write on, the gasoline used in the cars you ride in, and the air you breathe have in common? Water, trees used to make paper, crude oil used to make gasoline, and air are just a few examples of Earth’s resources. Can you think of other examples of Earth’s resources?

6. The Earth provides almost everything needed for life. For example, the Earth’s atmosphere provides the air you breathe, maintains air temperatures, and produces rain. The oceans and other waters of the Earth give you food and needed water. The solid part of the Earth gives nutrients, such as potassium, to the plants you eat. These resources that the Earth provides for you are called natural resources. A natural resource is any natural material that is used by humans. Examples of natural resources are water, petroleum, minerals, forests, and animals. Most resources are changed and made into products that make people’s lives more comfortable and convenient. The energy we get from many of these resources, such as gasoline and wind, ultimately comes from the sun’s energy.

7. Some natural resources can be renewed. A renewable resource is a natural resource that can be replaced at the same rate at which the resource is used. Figure 2 shows two examples of renewable resources. Although many resources are renewable, they still can be used up before they can be renewed. Trees, for example, are renewable. However, some forests are being cut down faster than new forests can grow to replace them.

8. Not all of Earth’s natural resources are renewable. A nonrenewable resource is a resource that forms at a rate that is much slower than the rate at which it is consumed. Coal, shown in Figure 3, is an example of a nonrenewable resource. It takes millions of years for coal to form. Once coal is used up, it is no longer available. Petroleum and natural gas are other examples of nonrenewable resources. When these resources become scarce, humans will have to find other resources to replace them.

9. Whether the natural resources you use are renewable or nonrenewable, you should be careful how you use them. To conserve natural resources, you should try to use them only when necessary. For example, leaving the faucet on while brushing your teeth wastes clean water. Turning the faucet on only to rinse your brush saves water that you may need for other uses. Conserving resources also means taking care of the resources even when you are not using them. For example, it is important to keep lakes, rivers, and other water resources free of pollution. Polluted lakes and rivers can affect the water you drink. Also, polluted water resources can harm the plants and animals, including humans, that depend on them to survive.

10. The energy we use to heat our homes, drive our cars, and run our computers comes from natural resources. The way in which we choose to use energy on a daily basis affects the availability of the natural resources. Most of the natural resources that provide us energy are nonrenewable resources. So, if we don’t limit our use of energy now, the resources may not be available in the future. As with all natural resources, conserving energy is important. You can conserve energy by being careful to use only the resources that you need. For example, turn lights off when you are not using them and make sure the washing machine is full before you start it. You can also ride a bike, walk, or take a bus because these methods use fewer resources than a car does.

11. Another way to conserve natural resources is to recycle. Recycling is the process of reusing materials from waste or scrap. Recycling reduces the amount of natural resources that must be obtained from the Earth. For example, recycling paper reduces the number of trees that must be cut down to make new paper products. Recycling also conserves energy. Though energy is required to recycle materials, it takes less energy to recycle an aluminum can than it does to make a new one!

12. Newspaper, aluminum cans, most plastic containers, and cardboard boxes can be recycled. Most plastic containers have a number on them. This number informs you whether the item can be recycled. Plastic products with the numbers 1 and 2 can be recycled in most communities. Check with your community’s recycling center to see what kinds of materials the center recycles.

13. Section Summary • We use natural resources such as water, petroleum, and lumber to make our lives more comfortable and convenient. • Renewable resources can be replaced within a relatively short period of time, but nonrenewable resources may take thousands or even millions of years to form. • Natural resources can be conserved by using only what is needed, taking care of resources, and recycling.