Clouds are the white-coloured structures that can be seen in the sky with our eyes. These structures are formed by the process of condensation.
With the increase in height the air gets cooler. Due to this the water vapor present here condenses to form a tiny drops of water known as droplets.
These droplets that float in the air are known as clouds.
When these droplets come closer to each other, they form a large size of drops. Due to this, some of the drops become heavy and begin to fall. These drops that fall is known as rain.
Return of water to the earth
Under certain conditions, they also fall as hail or snow. Thus, the water that evaporates into the atmosphere returns as rain by forming clouds.
Return of water to the oceans
When compared to the oceans, most of the land surfaces are above the oceans. Naturally, the rain and snow that falls on the earth returns to the seas in many ways.
The snow covering the mountains melts down into water and flows down in the form of streams and rivers. The rainwater also joins these long-distance running rivers and streams, and finally enter the seas and oceans.
Rainwater that gets absorbed in the ground may or may not be brought back to the atmosphere by the process of evaporation and transpiration. This water stored as groundwater which is a source for some of the lakes and open wells.
The ground water is a renewable resource as it is renewed by the rainfall.
In a few areas where there are many tube wells and hand pumps, one has to dig deeper to find the groundwater due to its over-usage.
The rainwater flows away quickly by removing the top layer of soil in the areas with a very little or no vegetation. In the areas that are covered by concrete, the seepage of the rainwater into the ground is reduced. This affects the availability of the groundwater.
Thus, the water that brought back to the surface of the earth by rain or snow reaches the oceans.