There is various use of water. Apart from drinking, there are so many activities for which we use water.
We may use a mug, a glass, a bucket or any other container to measure the amount of water used also we need water not only for our daily activities but also for producing many things.
We can get water from many sources like water from a river, spring, pond, well or a hand pump. Some others might say, ‘We get water from taps‘.
Also drawn from a lake or a river or a well. The water in the oceans and seas has many salts dissolved in it−the water is saline. So, it is not fit for drinking and other domestic, agricultural and industrial needs.
Disappearing Trick of Water
Water disappears from wet clothes as they dry up. Water from wet roads, rooftops and a few other places also disappears after the rains.
Water vapours so formed become a part of the air and cannot usually be seen.
During the daytime, sunlight falls on the water in oceans, rivers, lakes and ponds. The fields and other land areas also receive sunlight. As a result, water from all these places continuously changes into vapour. However, the salts dissolved in the water are left behind.
Evaporation takes place from all open surfaces of water. As a result, water vapour gets continuously added to air.
Loss of Water by Plants
Plants use a part of water to prepare their food and retain some of it in their different parts. Remaining part of this water is released by the plants into air, as water vapour through the process of transpiration.
Water vapour enters the air through the processes of evaporation and transpiration.
How are clouds formed?
The cold surface of the glass containing iced water, cools the air around it, and the water vapour of the air condenses. The process of condensation plays an important role in bringing water back to the surface of earth.
When the air moves up, it gets cooler and cooler. At sufficient heights, the air becomes so cool that the water vapour present in it condenses to form tiny drops of water called droplets. It is these tiny droplets that remain floating in air and appear to us as clouds.
Water in the form of vapour goes into air by evaporation and transpiration, forms clouds, and then comes back to the ground as rain, hail or snow.
Almost all land surfaces are above the level of oceans. Most of the water that falls on the land as rain and snow sooner or later goes back to the oceans.
Some of the water that falls on land as rain, also flows in the form of rivers and streams. Most of the rivers cover long distances on land and ultimately fall into a sea or an ocean.
Most of this type of water becomes available to us as ground water. Open wells are fed by ground water. Ground water is the source for many lakes as well. It is also this ground water which is drawn by a hand-pump or a tube-well.
Water from the ocean and surface of the earth goes into air as vapour; returns as rain, hail or snow and finally goes back to the oceans. The circulation of water in this manner is known as the water cycle. This circulation of water between ocean and land is a continuous process. This maintains the supply of water on land.
The time, duration and the amount of rainfall varies from place to place. In some parts of the world it rains throughout the year while there are places where it rains only for a few days.
Rains may lead to rise in the level of water in rivers, lakes and ponds. The water may then spread over large areas causing floods. The crop fields, forests, villages, and cities may get submerged by water.
The level of water in ponds and wells of the region goes down and some of them may even dry up. The ground water may also become scarce.
A small fraction of water available on the Earth is fit for use of plants, animals and humans. Most of the water is in the oceans and it cannot be used directly. When the level of the ground water decreases drastically, this can not be used any more.
Increasing the availability of water is to collect rainwater and store it for later use. Collecting rainwater in this way is called rainwater harvesting. The basic idea behind rainwater harvesting is “Catch water where it falls”.
A lot of effort will then be required to get this water back into our homes as the water did not seep into the ground.