The mantle is 2,900 km thick and makes up 85% of the Earth's weight. It is made of molten rock, iron, minerals, and other semi-solid rocks. The rocks rise heating the Earth then fall back down to the core to reheat.
The outer core is 2,300 km thick. It is a liquid layer. It surrounds the inner core. This layer is made of molten iron and nickel. Temperatures range from 4,000 to 5,000 degrees celsuis.
The inner core is 1,250 km thick. Temperature is about 6,000 degrees celsius, the same temperature as the center of the Sun. It is made of iron. This layer is solid due to the pressure of Earth.