The Earth is a wonderful combination of hard and liquid layers. It is made up of a core, mantel and crust.
The core is pressed into a solid mass of nickle and iron. It is solid from the pressure from the outer layers. The outer core is liquid material made mostly of nickle and iron. Next is the mantle, which is a combination of rocks and soil with liquid material towards the crust.
Here is a printout of the layers of the Earth.
Make a plasticine model of the Earth's layers using this printout for a hands on experience.