Radiation from the sun causes water to evaporate from the water bodies in the form of water vapour. From plants, water continues to evaporate into air. This is done through the process of transpiration. Some water vapour is also retained by air. When the water vapour in the air rises up it combines to form clouds. In the clouds, there is moisture, i.e. water, which may fall on earth in form of rain, hail or snow. Some rain water that falls to the ground gets absorbed by the soil to form underground water.
The remaining water reaches the water bodies (river, ponds, lakes and oceans). This is the hydrological or water cycle that continues in nature all the time.
