Water cycle
Have you ever wondered where our water comes from and where it goes to?
Water is recycled in nature every day, with the oceans and seas acting as giant recycling plants as water evaporates, falls as rain and finally runs back to the seas.
There is no such thing as new water – the water we use today is the same water that was in circulation in the Ice Age and is in fact nearly as old as the earth! The water cycle is a continuous process of evaporation and transpiration, condensation, precipitation and collection:
Evaporation
When the sun heats up water in rivers, lakes, seas or the ocean, it evaporates and turns into vapour or steam which rises through the air. At every stage of the water cycle, some water evaporates to begin the cycle again.
Transpiration
Transpiration is the process by which plants lose water out of their leaves, which helps the evaporation process of putting more water vapour into the air.
Condensation
As the water vapour rises it gets cold and changes back into liquid, forming clouds in a process called condensation.
Precipitation
Precipitation occurs when so much water has condensed that the air cannot hold it anymore. The clouds get heavy and water falls back to earth in the form of rain, hail, sleet or snow.
Collection
When the water falls back to earth as rain, it falls into rivers, lakes and oceans or ends up on the land. When it falls on land it either soaks into the ground and helps fill underground aquifers, from where we take water supplies, or runs over ground until it reaches lakes or rivers – where the water cycle starts all over again.