Water Cycle: Various cycles

Even though most of Earth is covered with water, the amount of water available on Earth is limited. This water keeps on changing from one form to another. The water cycle is the journey that water takes as it circulates from the land to the sky, and then back on the land again.

Water cycle includes four main stages – evaporation, condensation, precipitation and collection. Let’s look at each of these stages.

• Evaporation: The heat from the sun causes water in the oceans, lakes, rivers, streams, ice and soils to rise into the air as water vapour (gas). This is the process of evaporation (water turns from liquid to gas).

• Condensation: Due to lower temperature (at a height), water vapour in the air cools down and turns back into liquid water (from gas). When water vapour in the air cools down, tiny droplets of water are formed. The water droplets join to form clouds. This is the process of condensation.

• Precipitation: When these clouds become very heavy with a lot of water, it falls down in the form of rain or snow. This is the process of precipitation.  Water (in the form of rain, snow, hail or sleet) falls from clouds in the sky.

• Collection: Water that falls from the clouds as rain, snow, hail or sleet, again gets collected on Earth in the oceans, rivers, lakes, streams. Water also gets collected under the ground (seeping through the surface) as underground water.

The water evaporates and reaches the sky again, and the cycle continues. The continuous cycle by which water circulates, by the process of evaporation, condensation and precipitation, is known as water cycle.

These are the main stage in the water cycle, and the entire thing is powered by the sun (through its energy) and by gravity.

Sun’s heat starts the cycle by evaporating Earth’s water, which later gets converted into clouds. And its Gravity that gets all the water back on Earth.