1. The Earth is made up of a variety of materials, such as rocks, minerals, and metals. People can use these resources in many ways—but first, they have to get them.
2. We get many earth materials by digging into the earth’s crust. The earth’s crust is a thin layer of solid rock that makes up the earth’s outer layer. It is about 20 miles (32 km) thick.
3. Rock is made of one or more minerals stuck together. Minerals are solid, nonliving substances found in the earth’s crust. A mineral is made of elements and compounds. For example, limestone is a mineral made up of calcium, carbon, and oxygen. An element is a basic substance made of only one kind of matter.
4. People use rocks to build things, such as stone walls. Rocks are also used to make other building materials, such as concrete.
5. Minerals have many uses. For example, table salt is used to make food taste better. Minerals such as diamonds and gemstones are used to make jewelry. Because they are so hard, diamonds are also used in drills or cutting machines. Coins are made from pure metals such as gold and silver. Each of these metals is made of a single element.
6. Can you give two examples of metals used to build things like bridges and automobiles? People also use the earth as a source of energy. For example, the inside of the earth is so hot that its heat can be used to boil water. Boiling water makes steam. Steam is a force that can be used to produce electricity. The energy in hot water can also be used to heat homes. Some of the earth’s minerals are also used as a source of energy. For example, radioactive elements like uranium are used to produce nuclear energy. Fossil fuels like fuel oil and coal also come from the earth.
7. The water that covers most of the surface of the earth is another natural resource. We use the oceans in transporting goods and people by boat. If necessary, we can remove the salt to make drinking water. We can even use the motion of ocean waves to produce electricity.
8. The circle graph below shows the major elements that make up the earth’s crust. About how much of the earth’s crust is made up of oxygen?
Parent Tip: Review the logic above to help your child master the concept of worksheet for 8th grade science.
