Page 158 - Science Class 07
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plant or crop can be grown in the region if AVAILABILITY OF WATER
there is no water. In the Great Himalayan Let’s read about some interes ng facts related
Desert or Thar Desert, a few vegeta on are to the availability of water on the earth:
found because these parts of the earth have
v About 71% of the earth’s surface is covered
very li le water. Water is also used in industries
with water.
on a large scale to produce goods as well as
electricity. Specially in tex le industry and v About 97.2% of the total available water is
paper industry, water is used on a large scale. present in the seas and oceans which is
Water is needed both in thermal power plants salty and we cannot use this water for
and hydroelectric plants. In thermal power domes c purposes or agricultural purposes.
plants, water is converted into steam and the v About 2.07% of the total water is locked in
force of steam is used to rotate the turbines. glaciers and ice-caps.
v Rest water which is less than 1% is available
in the rivers, lakes, ponds and in the form
of ground water.
v We use water of the rivers, lakes, ponds,
and underground water for domes c
pruposes.
v Water cannot be produced by our use.
It circulates in the nature by the process
of evapora on, condensa on and
Thermal Power Plant precipita on. Circula on of water in the
But in hydroelectric plants, the force of moving nature is called water cycle.
water is used to rotate the turbines. Thus,
v Deforesta on causes low rainfall.
water, is one of the most important natural
v The amount of fresh water is reducing day-
resources which is essen al for economic
by-day due to water pollu on.
development of a country.
1. Why water is called life giving liquid?
2. What are the uses of water?
3. How was water formed on the earth?
4. What is the need of water in our body?
5. How does water help in economic development?
Water Source Volume (thousand of Km³) % % of total water
Ocean and seas 317,000,000 97.27
Ice and snow 7,000,000 2.10
158 Science-7
