Describe the water cycle.
- The water cycle is the journey water takes as it circulates from the land to the sky and back again. It involves the following steps:
- The Sun’s heat provides the energy for evaporation of water from the Earth’s surface (oceans, lakes, rivers, etc.)
- Plants also lose water into the air by the process of transpiration.
- Wind carries the moisture laden air. The water vapour eventually condenses forming tiny droplets in clouds. When clouds meet cool air over the land, precipitation (rain, hail or snow) is triggered and water returns to the land in the form of rainfall.
- All water that falls on the land does not immediately flow back into the sea. Some water seeps into the ground. Some of the underground water is trapped between rocks or clay layers. This is called ground water. Some of this ground water finds its way to the surface through springs. We also bring the ground water to the surface for our use through wells or tube wells. Water is also used by terrestrial animals and plants for various life processes. Most of the water flows down the hills as run offs (above the ground or underground), eventually returning to the seas as slightly salty water