Importance of water is as important as air because water is needed by all living things. Life is not possible without it. We use water in many ways such as for drinking, cleaning, washing, etc. It is found in lakes, seas, wells, ponds, rivers and underground. Rain is the main source of water.
What are the different forms of water?
Water is found in three states – solid (ice), liquid (water which we drink) and gas (water vapour).
Ice is the solid form of water and it has a fixed shape. When we put some water in the freezer in the refrigerator then after sometime, it changes into ice. When ice melts, it again changes into the liquid form (water).
We use the liquid form of water for drinking, washing, cleaning, etc. (importance of water). It flows. It has no definite shape. It takes the shape of the container into which it is poured. Pure water is colourless.
Let us observe a glass filled with water very carefully. We notice that water takes the shape as the shape of a glass. If we fill it in a cup, it takes the shape of the cup.
Gas (water vapour):
Do we know what happens when we boil water? When the water is heated, it changes into the water vapour. We can see this vapour coming out and this water vapour is a gas. The conversion of water into water vapour is called evaporation. Now with the help of an elder to hold a cool plate over water vapour, in a few minutes, we will see many drops of water deposited on the plate.
It happens because water vapour touches the surface of the cool plate, it again changes into water drops. This conversion of water vapour into water drops is called condensation.
So, ice, water and water vapour are the three forms of water.
Process of water cycle:
We know the heat of the Sun warms the water in the rivers, ponds, etc., and forms water vapour. The water vapour mixes with the air and goes high up in the atmosphere where the air is cool. In the presence of cool air, it condenses to form small water drops. These small water drops combine together and form clouds. When these clouds pass through the very cool air, the water drops become big and heavy. These heavy and big water drops come on the Earth in the form of rain. Some of the rain water goes under the ground while most of the rain water flows and fills the rivers, ponds, etc. This water again evaporates by the heat of the Sun. It again goes up and rains. This process continues and is known as water cycle.
What is snow or hail?
The air high up is very cold. Sometimes when these rain drops pass through the very cold region, it freezes as snow and falls down to the Earth as snow or hail.