The crust is Earth's solid and rocky outer layer that includes land and the ocean floor. If you pretended that a basketball was Earth's interior and dipped it in a bucket of water and then pulled it out again, the layer of water is about how thin the crust is compared to the rest of the Earth. It averages 32 kilometers thick.
The mantle is the next layer in. It goes about halfway through Earth. Physical conditions in the mantle change because pressure and temperature increase with depth.
The core is the innermost layer in Earth's interior. Scientists have estimated that the temperature of the core ranges from 2000 to 5000o C. If these estimates are correct, then the core may be as hot as the sun's surface.