1. Water (from oceans, rivers ponds etc) changes into water vapor due to heat of the sun and moves into the atmosphere by the process of evaporation.
2. Water is also added to the atmosphere by transpiration. It is a process by which excess water absorbed by plant roots is released through the pores on the surface of leaves.
3. These water vapors rise up and due to colder air in the upper atmosphere; it cools down and forms clouds. This process is called condensation.
4. As condensation proceeds, water vapor changes into water droplets.
5. When enough water droplets accumulate, they fall down as rain. This process is called precipitation.
6. The rain replenishes the water in the lakes, ponds, oceans, and other water bodies. The process of rain water thus entering the soil is known as infiltration.
7. When rain water flows over the surface of land before entering the water bodies, it is called surface runoff. At very low temperatures, water freezes and falls down as hail, snow, or sleet.