The Chemical Makeup of Layers The materials of the earth's interior form layers. The layers are made of different substances.  Scientists classify three main layers according to their location from the outside to the center of  the earth. 1. The crust is the outermost layer of the earth. It is the layer that you live on.  2. The mantle is the middle layer of the earth. The mantle is much hotter and has the ability to flow.  3. The center layer of the earth is the core.

The crust is made of rocky materials called silicates. (Silicates are compounds of silicon, oxygen and other materials.)
The crust is rich in aluminum, iron, and magnesium.
The mantle is made of rocky materials called silicates, but its silicates contain mostly iron and magnesium.
The core is made of mostly of the metals iron and nickel.

The Earth's Crust is like the skin of an apple. It is very thin in comparison to the other three layers.  The crust is only about 3-5 miles (8 kilometers) thick under the oceans(oceanic crust) and about 25 miles (32 kilometers) thick under the continents (continental crust).  Notice how thin the crust of the Earth is in comparison to the other layers.

Questions for Chemical Makeup of Earth's Layers
Use the web page and your textbook page 56.

1.  How thick is the crust, and what does it contain?

2.  What materials does the mantle contain?

3.  How much of the earth's volume does the mantle make up?

4.  How much of the earth's mass does the mantle make up?

5.  Which layer is more dense, the mantle or the core?  How
     do you know?

6.  What materials account for the density of the earth's core?
 
 

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