Earth Layers

If you could cut Earth in half, you would find it made up of layers. At its center is a solid core of metal, which is surrounded by a liquid metal core. The liquid core spins as the earth rotates, which creates Earth's magnetic field. Together, these two parts of the core are about 2,200 miles (3,520 km) thick and unimaginably hot.

A layer called the mantle covers the cores. It is semisolid and about 1,800 miles (2,880 km) thick. The mantle is much cooler than the core, but it is still so hot that some of the rock is molten (liquid).

A brittle crust of solid rock covers the mantle. Even though it is about 25 miles thick beneath the continents and 4 miles thick under the oceans, it is very thin in comparison to Earth's size. All life on Earth exists on the top layer of this crust.

So where are the plates? The uppermost part of the mantle is more solid and cooler than the rest of the mantle. It combines with the thin, solid crust to form a layer called the lithosphere. It is this layer that has been broken into pieces, or tectonic plates. These plates float on a part of the mantle that is made mostly of melted rock. Although we cannot feel it, the plates are slowly, but constantly, moving––carrying with them the continents and oceans that rest on Earth's crust.

Move the mouse over a label to highlight that part of the drawing.