Under the action of the sun, the water in the seas, lakes and rivers evaporates. Plants and living beings perspire and also reject water vapour.

Evaporated water rises into the air and condenses in the form of clouds made up of billions of droplets of water. These clouds are transported by the wind.

Infiltration: Water finally falls back onto the Earth, in the form of rain, snow, hail and even drizzle. It then streams over the ground, is absorbed by the vegetation, penetrates into the water tables and supplies the rivers, lakes and oceans.