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Water
Chapter 14 For us
Water is the basic necessity of life. Without water life is not possible on Earth. Life on
Earth started in water. A large number of creatures live in rivers, seas, oceans and
other water bodies. Our body is about two-third water! Water helps our body to
func on properly and keeps us healthy.
Plants also need water. Plants need water to make food. When you crush a few leaves
your hands become s cky. It is because of the presence of water in the leaves.
Water exists in diļ¬erent forms on the Earth. It exists in the air as water vapour and in
the ground as soil moisture.
Have you seen a ke le boiling? Steam comes out through the spout of the ke le. If it
con nues to boil for a long me, the water in the ke le will
become less. Water changes into water vapour. This
process is called evapora on. When the water vapour rising
from hot water comes in contact with the cool lid, it
changes back into water droplets. This process is called
condensa on. Did you know that though the major part of
the Earth's surface is covered with water, very li le can be
used by us? Freshwater available for us is as li le as a drop in a bucket! Most of the
Earth's water is present as saltwater in the seas and oceans.
Why do we not drink sea water?
We cannot drink sea water because it is very salty. In order to make it drinkable, salt
has to be removed from sea water. Through a process called desalina on, salty water
can be made fresh water. In this process salt is removed from sea water but the
process of desalina on is very expensive.
Do you know how do we get salt which we use in our food?
Salt is obtained from the sea water in salt farms. The sea water is trapped in an enclosed
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