Layers of the Earth

Layers of the Earth

Journey to the Center of the Earth

Watch the movie trailer for Journey to the Center of the Earth. Identify characteristics that you think are true and those you think are not true. Be prepared to share.

Essential Question:

How are layers of the Earth different from one another?

AKS 2f. Ask questions to Compare and contrast the Earth’s crust, mantle, and core including temperature, density, thickness, and composition.

The Earth is made up of 3 main layers:

Crust

Mantle

Core

Think of the layers of the Earth like the layers of a cake.

Draw the Layers of the Earth in your notebook. Include the DOWN arrow!

Crust

• Thinnest layer of the Earth that ranges from only 2 miles in some areas of the ocean floor to 75 miles deep under mountains

• Made up of large amounts of silicon and aluminum

• Two types of crust: oceanic crust and continental crust

• Composed of plates on which the continents and oceans rest

The Earth’s crust is like the skin of an apple. Turn to an elbow partner and discuss why this statement is true. Next, come up with another example.

Mantle

• Solid but capable of flow (like hot asphalt or fudge)

• Thickest layer of the Earth (making up 70% of the Earth’s mass)

• The hot material (magma) in the mantle rises to the top of the mantle, cools, then sinks, reheats, and rises again. These convection currents cause changes in the Earth’s surface

Outer Core

• Molten (liquid) metal that is about 4,700°C (8,500°F)

• Located about 1,800 miles beneath the crust and is about 1,400 miles thick

• Composed of the melted metals nickel and iron

Inner Core

• Solid sphere composed mostly of iron

• It is believed to be as hot as 6,650°C (12,000°F)

• Heat in the core is probably generated by the radioactive decay of uranium and other elements

• It is solid because of the pressure from the outer core, mantle, and crust compressing it tremendously

The Earth is like a peach or a boiled egg. Discuss. Come up with another analogy and be prepared to share.

Which layer of the Earth has the greatest temperature, pressure, and density?

Which layer of the Earth has the greatest temperature, pressure, and density?

Summary

The earth is layered with a lithosphere (crust and uppermost mantle), convecting mantle, and a dense metallic core. 

Pressure, temperature, and density increase as depth increases.