Water is essential for life as we know it. It is present throughout the Solar System, and was part of the Earth from its formation. The source of the water was the same as the source of the Earth's rock: the cloud particles which condensed in the origin of the Solar System.
This is the process that water starts and ends in the water cycle.
- The cycle starts when water on the surface of the Earth evaporates. Evaporation means the sun heats the water which turns into a gas.
- Then, water collects as water vapour in the sky. This makes clouds.
- Next, the water in the clouds gets cold. This makes it become liquid again. This process is called condensation.
- Then, the water falls from the sky as rain, snow, sleet or hail. This is called precipitation.
- The water sinks into the surface and also collects into lakes, oceans, or aquifers. It evaporates again and continues the cycle.
- This whole process in which water evaporate and falls on the land and later flows back in river and pond is known as water cycle.