Earth S Interior

Earth’s Interior

On a separate sheet of paper, explain how geologists know that Earth’s core is made up of two parts.

17C Name Date Class

Earth’s Interior

Understanding Main Ideas Label the layers of Earth by writing the name of the layer in the blank. On a separate sheet of paper, write a description for each layer.

Answer the following questions on a separate sheet of paper.

5. What are two types of evidence geologists use to learn about Earth’s interior? 6. Compare how pressure and temperature change with depth inside Earth.

Building Vocabulary Match each term with its definition by writing the letter of the correct definition in the right column on the line beside the term in the left column.

7. basalt a. a dark rock with fine grains

8. crust b. the force pressing on an area

9. outer core c. the layer made up of molten iron and nickel

10. granite d. a rock with light color and coarse grains

11. pressure e. Earth’s outer skin of rock

12. seismic wave f. a wave produced by an earthquake

13. inner core g. a layer of hot, solid rock below the crust

14. mantle h. a dense ball of solid iron and nickel 17D Name Date Class

Earth’s Interior

Read the passage and look at the diagram below it. On a separate sheet of paper, use the diagram to answer the questions that follow.

Difference in Arrival Time Geologists have learned a great deal about the Earth’s interior by carefully studying the waves created by earthquakes, called seismic waves. Like light waves and sound waves, seismic waves travel through different kinds of materials at different rates. For example, a type of seismic wave called a P wave travels through crust material at an average speed of 6 km/s. But through the uppermost mantle material, P waves travel at an average of 8 km/s. Geologists use their knowledge of this difference in speeds to explore the interior of Earth. They have set up thousands of receiving stations to record the arrival of seismic waves. Computers then help in analyzing the data and creating a picture of Earth’s interior. The diagram shows two P waves from an earthquake whose travel times are recorded by a receiving station.

1. How far away from the earthquake is the receiving station? 2. Which P wave takes a more direct route to the receiving station, Wave A or Wave B? 3. How long does Wave A take to reach the station? 4. Wave B took 51 seconds to arrive at the station. What accounts for the difference in arrival times between Wave A and Wave B? 5. Can you infer why P waves travel faster through the upper mantle than they do through the crust? 17E Name Date Class

Earth’s Interior

If the statement is true, write true. If the statement is false, change the underlined word or words to make the statement true.

1. Earth’s core is mostly made up of iron and magnesium.

2. Scientists think that movements in the liquid inner core create Earth’s magnetic field.

3. The oceanic crust is most like granite in composition overall.

4. Pressure and temperature increase as you move deeper below Earth’s surface.

5. To learn about Earth’s interior, geologists study how seismic waves move through Earth.

6. The core is Earth’s outer skin of solid rock.

Write the letter of the correct answer on the line at the left.

7. In which layer of Earth is the asthenosphere located? 8. Which lists the main layers of Earth in order from outermost to innermost? A inner core A lithosphere, asthenosphere, mesosphere B mantle B core, mantle, crust C outer core C crust, mantle, core D crust D mantle, core, crust

9. Which best describes the mantle? 10. What do geologists call the crust and A molten metal uppermost mantle? B dense, solid metal ball A lithosphere C hot but solid rock B asthenosphere D dry land and ocean floor C mesosphere D outer cor3