1. Layers of the Earth

2. The Earth’s Interior
Most scientists agree that soon after Earth’s formation, Earth was a large ball of molten (melted) rock. As time passed, the molten materials cooled, hardened, and separated into layers.
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3. Composition (What it is made of)
Crust
Mantle
Core

4. The Crust Thin, outer layer that covers the planet 8 - 32 km thick
2 types of crust
Oceanic (very dense, made of basalt)
Continental (less dense, made of granite)

5. Oceanic and Continental Crust

6. The Mantle Middle layer Very thick layer (2900 km thick)
Made of silicon, oxygen, iron, magnesium
- solid that has the ability to flow = plasticity

7. The Core Central part of the planet Made of iron and nickel
1/3 of the earth’s mass
Very hot
- inner core = solid
- outer core = liquid

8. Earth’s Layers How are the earth’s layers similar to an egg?
Shell=crust
Egg white=mantle
Yolk=core

9. Physical Structure of the Earth (5 Layers)
Lithosphere- rigid outer layer (crust)
Asthenosphere- solid rock that flows slowly (like hot asphalt)
Mesosphere- middle layer
Outer Core- liquid layer
Inner Core- solid, very dense

10. Do scientists travel to the inside of Earth to learn about the layers?
High temperatures and tremendous pressure in the Earth’s interior would make traveling there and remaining alive impossible.
Even the deepest oil wells are only a few kilometers deep, and the diameter of the Earth is 12,756 km.

11. So, how do we know about the layers?
Seismic waves are when vibrations are released by earthquakes. Scientists can study the speed and path of these waves and use that information to infer what is inside our Earth.