Layers of the Earth for Kids: Crust, Mantle and Core (Grade 6 to Grade 8 Science)

Hi, I'm Luna from DoodleBeez. If you could dig straight down about six thousand four hundred kilometers, you would reach the center of the Earth. Today we will travel through Earth's layers, all the way to the core.

The crust is the thin, rocky outer layer we live on. Under the oceans, it is only about five to ten kilometers thick. Under the continents, it is usually thirty to fifty kilometers thick, and thicker under mountains.

Below the crust is the mantle, the thickest layer, nearly three thousand kilometers deep. It is mostly solid rock, but it is so hot that parts of it flow very slowly, like thick putty, over millions of years.

The crust and the very top of the mantle form rigid tectonic plates. Slow movement in the mantle helps carry these plates a few centimeters each year, causing earthquakes, volcanoes and new mountains.

Below the mantle is the core, made mostly of iron and nickel. The outer core is liquid, and its swirling metal creates Earth's magnetic field. The inner core is solid, squeezed by enormous pressure, though it is over five thousand degrees.

How do we know all this? Nobody has dug that deep. Scientists study earthquake waves. These waves change speed and direction in different layers, and some of them cannot pass through the liquid outer core.

Now it's your turn. Which layer is made of liquid metal and creates Earth's magnetic field: the crust, the mantle, the outer core or the inner core? Pause and try. The outer core! Its swirling liquid iron makes the field.

Great job! Remember, Earth has a thin crust, a thick slowly flowing mantle, a liquid outer core and a solid inner core. Earthquake waves help us see inside. Practice Earth's layers in the Science Lab at doodlebeez.com. See you next time!