* Inner Core: This is the hottest part of the Earth, with temperatures reaching over 5,200° Celsius (9,392° Fahrenheit). The immense pressure at this depth is so great that it keeps the iron from turning to liquid, even though it's incredibly hot.
* Outer Core: Surrounding the inner core is the liquid outer core, also mostly composed of iron, but with some nickel and other elements. This layer is about 2,200 kilometers (1,367 miles) thick. The movement of the liquid iron in the outer core generates the Earth's magnetic field.
* Mantle: The mantle is the thickest layer of the Earth, making up about 84% of Earth's volume. It's mostly made up of silicate minerals and is solid but can flow very slowly over millions of years. This slow movement of the mantle is what drives plate tectonics.
* Crust: The crust is the outermost and thinnest layer of the Earth. It's what we live on and is divided into oceanic crust (thinner and denser) and continental crust (thicker and less dense).
So, in short, the centre of the Earth is a solid ball of iron called the inner core, surrounded by a liquid outer core.
