The Earth

The solar system

Facts about our Planet The earth is one of eight planets in the Solar System. The sun is at the centre of the solar system and all of the planets orbit the sun. More than 6 billion people live on our planet. 2/3 of the earth’s surface is covered by water. 1/8 of the earth’s surface is covered by deserts 1/10 of the earth’s surface is covered by mountains 1/4 of the earth’s surface is covered by forests.

Inside Planet Earth If we could cut through the earth like an apple we would see that it is made up of 3 different layers. These are called the, The Crust The Mantle The Core

The Earth’s Crust The crust is the outer skin of the earth. It is like the skin on a piece of fruit or the crust on bread. However, the earth’s crust is made up of a layer of solid rock 10-60km thick. This hard shell is where we live.

The Mantle Beneath the hard crust is a layer of hot, soft rock called the mantle. The rocks in the mantle are molten or melted because it is so hot (4000 C). This molten rock is called magma.

The Core Beneath the mantle, in the centre of the earth, we find the earth’s core. It is made of hot metals such as iron and nickel. The core can be divided into an inner and an outer core. The Outer Core is made of molten metals because is so hot. The Inner Core is made of solid metal because the pressure is so great.

The Earth’s Crust - Plates The earth’s crust is not an unbroken shell. It is made up of a number of different pieces, like the surface of a leather football. Each one of these pieces is called a Plate. The plates fit together like a jigsaw. Plates meet each other at plate boundaries. All of the plates have names, such as the Eurasian Plate and the American Plate.

The Earth’s Plates

Pacific ring of fire

The Earth’s Plates

Plate Movement The plates which make up the earth’s crust are continually moving. This is because the plates are floating on top of the molten (melted) rock of the Mantle. Convection currents within the mantle cause the molten rock to move, thus moving the plates floating on top of them. This movement is very slow, but it means that the plates continually collide, pull apart, and push past one another.

Convection currents in the mantle

Continental Drift We now know that the plates move because they are floating on top of the mantle. The continents, such as America and Africa, are attached to the American Plate and the African Plate. Therefore, when the plates move, the continents move too. This movement of the continents is called Continental Drift. Continental Drift is still occurring today. For e.g. Europe is still slowly moving away from America.