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Different Forms Of Water
FORMS OF WATER
Are you afraid that continuous use will some day exhaust all the water available for use? You know that water on the earth has been maintained for millions of years by various processes which make the water cycle. You have studied the water cycle in Class VI. Write in your own words what you know about the water cycle.
You know that when water circulates through the water cycle it can be found in all the three forms, i.e., solid, liquid and gas— at any given time somewhere on the earth. The solid form, snow and ice, is present as ice caps at the poles of
the earth, snow-covered mountains and glaciers. Liquid water is present in oceans, lakes, rivers, and even underground. The gaseous form is the water vapour present in the air around us. The continuous cycling of water among its three forms keeps the total amount of water on the earth constant even when the whole world is using it. Does it give you any relief?
Can you recall the processes involved in water cycle? The following activity will help you.
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Water Cycle
Activity 16.3
Fig. 16.5 shows the processes involved in the water cycle. They are labelled by numbers. Match these numbers with the processes given in the jumbled form. Most towns and cities have water supply system maintained by the civic bodies.
Fig. 16.5 Water cycle
The water is drawn from nearby lakes, rivers, ponds or wells. The water is supplied through a network of pipes. Many villages do not have such a water supply system. There people fetch water directly from the sources. Often people and even children have to walk several kilometres to fetch water (Fig. 16.6). The children suffer a lot. They cannot attend school regularly since they spend hours in fetching water.
A large number of people draw water from wells, tube wells or hand pumps. From where do these sources get water?