Earth's Interior

Earth's Interior

1. Exploring Inside Earth Geologists have used two main types of evidence to learn about Earth’s interior: Direct evidence from rock samples Indirect evidence from seismic waves .

2. Rocks from inside Earth give geologists clues about Earth’s structure . Evidence From Rock Samples Geologists have drilled holes, or blasted rock to bring up samples and make inferences about conditions deep inside the Earth . These rocks provide more information about the interior . But we can only drill and blast rock to a certain depth, which is not nearly deep enough to gain more perspective about the Earth’s interior.

3. Evidence From Seismic Waves Geologists cannot look inside Earth. Instead, they must rely on indirect methods of observation, they use seismic waves . When earthquakes occur, they produce seismic waves . Geologists record the seismic waves and study how they travel through Earth. The speed of seismic waves and the paths they take reveal the structure of the planet.

4. The three main layers of Earth are the crust , the mantle , and the core . These layers vary greatly in size , composition , temperature , and pressure . Temperature After about 20m of depth the temp. of the rock begins to gradually rise toward the center of the earth . Pressure As you move closer to the center of the earth pressure will gradually increase because the amount of rock above you increases. On the surface , the Earth resembles more of a cracked hardboiled egg prior to peeling the shell. EARTH’s INTERIOR

5. Earth is like a cracked hardboiled egg!

6. Lithospheric Plates The surface of Earth is made up of rigid plates that move relative to each other . Move together Move apart Slide past

7. Lithospheric Plates 1. Why is the Earth broken up into different pieces on the surface? 2. What is making the plates move relative to one another?

8. Convection Currents Heat from the Interior creates convection currents slowly moving rock due to density differences .