Description:
The inner structure of the Earth is formed of layers. Outermost is the crust, which is made of silicon. Beneath this is a semi-solid mantle made of melted rock, which flows slowly in circular patterns. Beneath this there are the outer and inner cores, which contain mostly iron and nickel. The inner core is thought to be completely solid and very dense, whereas the outer core is thought to be a thick liquid. It is this core which gives the Earth its magnetic field.