Water cycle or the hydrological cycle is a classic example of biogeochemical cycle involving the circulation of water between the atmosphere and the earth.
Water is circulated between the earth and the atmosphere by the processes of evaporation, condensation and precipitation. Evaporation is the transformation of water into water vapour from the water bodies and the plants through transpiration. The water vapour is then transformed into liquid water droplets in the air creating clouds and fog. The water droplets reach the earth through the process of precipitation in the form of rain. This cycle of evaporation, condensation and precipitation continues as a cycle called the hydrological cycle.