words bank:

The earth is made of different    layer  ; 4 layer. many researcher say that as the earth was cooling, the heavier   thick materials    sank  to  the  center  and    light material   rose  to  the  top .consequently,the lightest materials are made     crust   (basalt and granite rocks) and heavy    metals   are in the core(iron and nickel).

The layer that you live on, is the crust and it is the most known layer.The mantle has the  ability to    flow   and is much hotter. The    outer   and inner cores are hotter and if you were able to go to the center of the earth, because of very  high pressure ,you could squeezed it into a ball smaller than a marble smaller than a marble.