1. Let’s look at the Earth

2. The Inside of the Earth is made of Several Layers

3. The Inside of the Earth is made of Several Layers
The Crust:
A Thin Rock Material

4. The Inside of the Earth is made of Several Layers
The Mantle:
A Dense and Mostly Solid Rock Material

5. The Inside of the Earth is made of Several Layers
The Outer Core:
Liquid Iron and Nickel

6. The Inside of the Earth is made of Several Layers
The Inner Core:
Solid Iron and Nickel

7. How Do We Know This? The Crust: The Mantle: The Outer Core:
A Thin Rock Material
The Mantle:
A Dense and Mostly Solid Rock Material
The Outer Core:
Liquid Iron and Nickel
The Inner Core:
Solid Iron and Nickel

8. Why do the layers of the earth float on one another?
Density!!!!!

9. Density determines a layer’s location!
Why does any layer float?
Why does any layer sink?
It is less dense than the one under it!
It is more dense than the one above it!

10. Density

11. The Density of Earth is 5.53 gm/cm3

12. The Density of Earth is 5.53 gm/cm3
We know the surface of the Earth is covered with Rocks

13. The Density of Earth is 5.53 gm/cm3
The Land is covered mostly by a type of rock called Granite
(density of Granite = 2.6 gm/cm3)

14. The Density of Earth is 5.53 gm/cm3
The Land is covered mostly by a type of rock called Granite
(density of Granite = 2.6 gm/cm3)
The Ocean is mostly covered by a type of rock called Basalt
(density of Granite = 3.3 gm/cm3)

15. The Density of Earth is 5.53 gm/cm3
Granite = 2.7 gm/cm3
Basalt = 3.3 gm/cm3
Neither of these Rocks is dense enough to account for the density of the Earth

16. The Density of Earth is 5.53 gm/cm3
Granite = 2.7 gm/cm3
Basalt = 3.3 gm/cm3
Iron has a density of 7.9 gm/cm3

17. The Density of Earth is 5.53 gm/cm3
Granite = 2.7 gm/cm3
Basalt = 3.3 gm/cm3
Iron has a density of 7.9 gm/cm3
So we believe the inside of the Earth is made of a heavy element such as Iron or Nickel
(density of Nickel = 8.9 gm/cm3)

18. The Density of Earth is 5.53 gm/cm3
Density of Rocks  3 gm/cm3

19. The Density of Earth is 5.53 gm/cm3
Density of Rocks  3 gm/cm3
Density of Iron/Nickel  8 gm/cm3

20. Earth's Interior Structure
Average density
Crust
Mantle
Core
5.5 g/cm3
3 g/cm3
5 g/cm3
11 g/cm3

21. Density increases with depth !
Earth must have been molten once, allowing denser material to sink, as it started to cool and solidify.

22. The Density of Earth is 5.53 gm/cm3
Density of Rocks  3 gm/cm3
Density of Iron/Nickel  8 gm/cm3
So we believe about ½ the Earth is a Rock-like material and the other ½ a heavy metal such as iron and nickel
The density of the Earth will be the average of the two: