Earth’s Interior

Ch 2, Lesson 3

Layers

• Earth’s interior is made up of layers.

• Each layer has a different composition, pressure, and temperature.

Seismic Waves

• Scientist learned about the Earth’s layers using seismic waves from earthquakes.

• Wave’s speed and direction change when going through different materials (solid rock, liquid rock, solid metal, liquid metal)

Crust

• Thin, rocky, outer layer of Earth. – Two types:

• Continental crust (continents or land)• Oceanic crust (under the ocean)

Lithosphere

• The crust and the solid uppermost layer of the mantle.

Asthenosphere

• Heated rock under the crust. – Rock is heated so much it acts like

playdough.

Mantle

• The thick middle layer of Earth– Composed of rock

The Outer Core

• A layer of melted metal (iron and nickel)

• Denser than the mantle

The Outer Core

• Solid ball of iron.

• Earth’s densest layer.

• Temperature comparable to the surface of the sun!