crust - the rigid, rocky outer surface of the Earth, composed mostly of basalt and granite. The crust is thinner under the oceans.
inner core - the solid iron-nickel center of the Earth that is very hot and under great pressure.
mantle - a rocky layer located under the crust - it is composed of
silicon, oxygen, magnesium, iron, aluminum, and calcium. Convection (heat) currents carry heat from the hot inner mantle to
the cooler outer mantle.
outer core - the molten iron-nickel layer that surrounds the inner core.