Earth's Internal Structure

Crust

The thin, solid outer layer of the Earth

Continential crust

Thickness: Up to 70km thick

Less dense layer forming the continents and rich in felsic granite containing silicon & aluminum

Oceanic crust

Thickness: Up to 5-10km thick

Thin dense layer underlying ocean basins, mainly composed of matic basalt rich in magnesium & silica

Mantle

The thickest layer of the Earth; accounts most of its volume

State: Semi-solid

Composition: Made of hot, heavy, silicate rocks rich in iron & magnesium

Temp.: 870 degrees Celsius to 3000 degrees Celsius

Outer Core

A liquid layer situated beneath the mantle

State: Liquid

Composition: Primarily made up of liquid iron

Temp.: 5,500 degrees Celsius to 4000 degrees Celsius

Inner Core

A dense, solid sphere at the very centre of the Earth; very centre of the planet

State: Solid, because the extreme pressure squeezes it so tightly despite the heat

Composition: Composed mainly of solid iron & nickel

Temp.: 5000 degrees Celsius to 6000 degrees Celsius