Chapter 15 Section 5 How can natural resources be conserved? Objective: Describe ways to conserve natural resources.

Recycling Natural resources can be conserved by recycling, or by using them over again. Aluminum, glass, paper, and plastics can all be recycled. For example, when paper is recycled, fewer trees need to be cut down. Recycling also uses less energy than finding new resources. This conserves fossil fuels.

Recycling

Recycling Another way to conserve resources is to use other materials in their place. For example, some iron and aluminum parts in engines can be replaced with plastic. Some steel cables can be replaced by nylon ones.

DESCRIBE: How does recycling conserve natural resources?

New Mineral Sources Mineral resources on land are running out. However, the ocean may be a new source of minerals. Many minerals, such as sodium, sulfur, potassium, magnesium, and bromine, are dissolved in ocean water. Scientists are looking for less expensive ways to take minerals from the ocean.

New Mineral Sources Another new source of minerals might be space. Moon rocks contain aluminum, magnesium, titanium, and silicon. Asteroids may contain billions of tons of nickel and iron. Spacecraft have been sent to study asteroids with this in mind. Astronomers use special instruments to determine an asteroid’s mineral makeup.

2. LIST: What are some possible new sources of minerals?

Water Conservation The supply of clean, fresh water on Earth is limited. One way to conserve water is not to waste it. Do not run the water when you brush your teeth. Take showers rather than baths because showers use less water. Fix leaky faucets quickly.

3. STATE: What are two ways to conserve water?

Soil Conservation Some farming methods help conserve soil. For example, contour farming, farmers plow across the slope of the land. In terracing, flat areas, or terraces, are created on the side of a hill. Both of these methods help prevent water from washing away soil. In strip-cropping, grasses are planted between crops to hold water and help stop erosion.

Soil Conservation Windbreaks such as rows of trees help stop wind from blowing soil away. Fertilizers can replace the nutrients used up by plants. So can planting legumes.

4. NAME: What farming methods help conserve soil?

15-5 Classwork CHECKING CONCEPTS What process reuses natural resources? How can iron and aluminum engines be updated to conserve resources? What do fertilizers add to soil? What farming methods help stop water from washing away soil?

15-5 Classwork THINKING CRITICALLY 5. EXPLAIN: How does recycling reduce waste? 6. CALCULATE: About 90 new aluminum cans can be made from 100 recycled cans. If each person in you class recycled one can each day, how many new cans could be made from what your class recycled in a month?