The Structure of the Earth

The Earth is made up of 4 main layers:

-Outer Core
-Inner Core

The Crust

The Crust is the thin outermost layer that wraps around the Earth. It is split into two types, continental and oceanic.
Continental crust makes up the land on Earth, it is thicker (35 - 70 km), less dense and mostly made up of the rock granite.
Oceanic crust makes up most of the ocean, it is thinner (5 - 7 km), denser and mostly made up of the rock basalt.

The Mantle

Just below the crust lies the mantle. The mantle is semi-liquid, sort of like a malleable plastic and makes up 84% of Earth's volume.
It is broken down into 3 main zones, the lithosphere, asthenosphere, and mesosphere.
The lithosphere makes up both the lower part of the crust and upper part of the mantle. It consists of the 15 major tectonic plates on Earth.
The asthenosphere is where the mantle turns much more fluid.
The mesosphere is a part where temperatures and pressures get so high that the rock becomes more rigid.

Outer Core

Outer core is a fluid layer about 2,260 km thick, composed of mostly iron and nickel that lies above Earth's solid inner core and below its mantle.

Inner Core

Inner core is the innermost geologic layer of planet Earth. It is primarily a solid ball with a radius of about 1,220 km, which is about 20% of Earth's radius.
The temperature at the inner core's surface is estimated to be approximately 5,430 °C, which is about the temperature at the surface of the Sun.