Precipitation

Precipitation literally means falling from a height. In case of water, precipitation includes all forms in which atmospheric moisture descends to earth; rain, snow, hail, sleet and dew. The moisture that enters the atmosphere by the vaporisation of water condenses either into liquid (rain) or solid (snow, hail and sleet) before it can fall. Water returns to the land and the sea from the atmosphere by means of condensation, deposition and precipitation. Condensation is defined as the process by which water changes from vapour phase to a liquid state (in form of dew droplets). Deposition is the process by which water changes directly from a vapour into a solid (ice crystals) phase. In the atmosphere tiny droplets of water and ice crystals produced through condensation and deposition form clouds. You have to keep in mind that vaporisation absorbs energy (evaporation of sweat cools your body by using up excess body heat.) The energy used up in vaporisation is released when the water vapour condenses. The major amount of water on earth, is received as rainfall.

The water cycle in nature is sustained by energy from the sun. Solar energy evaporates water from the sea and the land. Water vapours condense in the atmosphere to form clouds which are transported to long distance by wind currents. Rainfall and melted snow replenish water in rivers, which cany it back to to sea.