# A Lesson On The Layers Of The Earth

## The Earth is made up of many layers. Find out what they are, their compositions,and depths in this lesson.

The Earth is made up of three main layers. They are the Crust, The Mantle, and the Core. This article will tell you about their depth, composition, temperature, and more. Read on to learn about the layers of the Earth.

The Earth has two types of crusts, or surfaces. They are the Continental Crust, which is the land we live on, and the Oceanic Crust, which is the bottom of the ocean. The Continental Crust extends from the surface downward for twenty-two miles. It is primarily composed of granite.

The Oceanic Crust extends from the surface (bottom of the ocean) downward for seven miles. It is composed mostly of basalt. The crust makes up .04 percent of the Earth's overall mass and less than one percent of the Earth's volume. The temperature average in the crust is 900 degrees Fahrenheit.

The Mantle is the next layer of the Earth past the crust. It is from 7 miles (or the bottom of the Oceanic Crust) to 1,800 miles. It is composed of iron and magnesium silicates. The Mantle accounts for 68.1% of the Earth's mass and 83% of the volume. The average temperature found here is 4,500 degrees Fahrenheit.

The Core is the middle of the Earth. There is a division of the Outer Core and the Inner Core. The Outer Cores extends from 1,800 miles to 3,200 miles. It is composed of liquid iron and nickel. It is said to be 9,000 degrees Fahrenheit. The Inner Core, or very center of the Earth, is from 3,200 miles to 3,960 miles. It is composed of solid iron and nickel. The average temperature here is 12,000 degrees Fahrenheit. Overall the Core accounts for 31.5 % of Earth's mass and 16% of the volume.

The Earth can also be classified a different way, by the physical properties of each layer, rather than the composition as we listed above. This way gives us four layers: the lithosphere, the asthenosphere, the mesosphere, and the core. The lithosphere is the Earth's cool outer layer, or the first 60 miles down. The asthenosphere is the hot, flowing layer and goes from 60 miles to 430 miles down. The mesosphere is the rigid hot layer. It is believed the pressure here keeps it from flowing. It is found from 430 miles to 1,800 miles. The core is also divided in this characterization as well to an outer and an inner. They are the same depths as the first way discussed. The outer layer is liquid and the inner layer a solid.

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