The Water Cycle

70% of the water in the world is found in oceans, seas, rivers or lakes. The water cycle circulates the water between the land, oceans and the atmosphere.

The water cycle is so called because no water is lost to the Earth, and no more water can be made. The water cycle is also continuous because it is happening all the time.

Water from seas, oceans and lakes is evaporated by the heat of the sun. Evaporation is where the water droplets are changed from a liquid to a vapour or a gas. This water vapour rises up into the atmosphere. As the water vapour rises, it begins to cool down to form water droplets again. This is condensation. Sometimes condensation forms on windows.

As water vapour condenses, there are more water droplets in the atmosphere. These water droplets join together to make clouds. There are several different types of clouds. The big heavy ones called cumulo-nimbus. Nimbo-stratus are the rain clouds. The high, wispy clouds are cirrus clouds and do not give rain.

The rain clouds blow inland over the hills and moutains and gather more water droplets. When the water droplets in the clouds become too big, they fall as rain. The rain either falls directly into rivers and lakes or it can trickle through the ground and eventually end up in a river or lake.

Water in the rivers and lakes is then taken to a Water Supply Works where it is cleaned before it can be used by the public. Once the water has been used for drinking, by factories, in homes and in agriculture it is classed as dirty water. This dirty water is taken to a Waste Water Treatment Works and treated before being discharged back into the river.

Some water is sent back out to sea by long sea outfall pipes (after treatment). The water in the river then discharges itself into the sea and the whole cycle starts again.