Earths Interior A long time ago What do

Earth’s Interior

A long time ago… What do you think Earth looked like 1, 000 years ago? • Same as today? • Drastically different? • Why?

Changing the Surface • The surface of the Earth has undergone many changes as a result of – Lifting – Pushing – Bending – breaking

Why? The answer lies inside the Earth.

Exploring Inside the Earth • Scientists have two types of evidence of Earth’s interior. 1. Rock Samples (direct evidence) – Drill down in the Earth to get samples • This tells us a little bit about the conditions deep within the Earth. – Some rocks are blasted to Earth’s surface. How? Volcanoes!

Exploring inside the Earth • Have you ever knocked on a wall to find the wooden stud behind it to hang a picture? • What are the differences in sound you hear when you get close to it? Farther away from it?

Exploring inside the Earth • Scientists experience something a little like that. 2. Seismic Waves (indirect evidence) – Scientists study how earthquake waves travel through the earth. – The speed and path they take tell us about the inner structure. – We know there are layers inside.

The layers of Earth • We also know the layers are different from each other in the following ways: – Size/thickness – Composition – Temperature* – Pressure*

Temperature and Pressure • Temperature increases with depth in the Earth. • Pressure also increases with depth inside the Earth due to all of the overlying rock layers (6, 000 km from surface to center). • Imagine being on the bottom row of a human pyramid compared to being on the very top!