Water evaporates when the sun shines on oceans, seas, or wet grounds or when wind blows over them. The water vapour rises up and gets converted again into tiny droplets on reaching the cold heights of the sky.
These tiny droplets form clouds which are carried here and there by the wind. If they rise further, such as on a high mountain crest, they become colder and turn into large raindrops, small ice crystals, and hailstones. These are heavy and fall to the ground as rain, and water seeps into the ground. This water returns to the sea as ground water, rivers, and streams. This cyclical process is known as the ‘water cycle’.