1. Earth Science 7
The Layers of the Earth

2. Layers of the Earth The Earth is composed of four different layers
The crust
The mantle
The outer core
The inner core

3. The Crust The crust is the solid surface on the outside of the planet
It ranges from 5 to 50 km thick
The crust has temperature ranging from 5°C Near the surface to 1000°C at its base

4. The Crust
The crust is less dense than the deeper layers of the Earth. This allows the crust to float on top of the Mantle
The boundary between the crust and mantle is the Moho (Mohorivicic Discontinuity)

5. The Mantle The Mantle is partly melted layer the layer below the crust
The mantle is ~2900 km thick and ranges from 1000ºC to ºC

6. The Mantle The upper mantle flows like chewy caramel
The deeper you go the denser the mantle gets because of the pressure of the layers above
The lower mantle doesn’t flow

7. The Core The core is divided into two layer: The outer core
The inner core

8. The Outer Core The outer core is ~2200 km thick
The temperature increases from 4000°C to 5500°C
It is an extremely dense liquid layer composed mostly of iron and nickel
The outer core’s outer layer flows

9. The Inner Core The inner core is the middle of the Earth
It is almost as hot as the surface of the sun, but kept solid by the pressure
It is 1250 km thick
It has a temperature of 6000ºC

10. Earthquake Evidence for Earth’s Structure
One piece of evidence for the structure of the Earth is the movement of P waves.
The time that seismic waves arrive at distant points doesn’t work for a uniform Earth

11. Review of the Earth’s Layers
The Earth has four layers:
The crust
The mantle
The outer core
The inner core
Each layer has a different temperature, thickness, and composition