The Earth

Earth’s structure

Core

- Centre of the earth

- Consists of inner and outer core

- Inner core

- 2200 km thick

- 10 000 C hot

- Iron and nickel

- Outer core

- 2200 km thick

- Metals- iron and nickel.

- 4000C- 6000 C hot

- Heat comes from nuclear reactions

- Gives earth the poles and magnetic field

Mantle

- 2800 km thick

- 500 C at the top

- 3000 C at the bottom

- Mostly silicates

- Solid Rock

Crust

- 7 km- 50 km thick

- Made up of rocks and minerals

- 200C- 400C hot

Lithosphere- The lithosphere is the solid outer shell of a planet. The earth's lithosphere consists of the crust and upper mantle, and is 100 km thick.

Rocks

Igneous rocks- Magma from inside the earth and lava from volcanic eruptions cool and solidify to form igneous rocks.

Intrusive igneous rocks- Intrusive igneous rocks form when magma becomes trapped in small pockets, and start to cool slowly.

Extrusive igneous rocks- Extrusive igneous rocks are formed when lava cools on earth’s surface. One example is pumice where it contains tiny holes which are formed by volcanic gases escaping from cooling lava.