Page 79 - ACTIVE SCIENCE 4 TOC

Some of the water that falls on the ground percolates or seeps underground and is
deposited as the water table under the earth.

Water Purification

Water contains substances like dirt, sand and germs which makes water impure.
Consuming such water can cause many diseases. Therefore, we should purify
water before drinking.

Boiling is the easiest method to purify water. It kills germs present in water.
After boiling, we should keep water in covered containers. Modern day filters are
also well equipped to have cold water.

S edimentation and Decantation
Percolation
Sedimentation and decantation are the

processes to separate impurities from water. In
sedimentation, we allow impure water to stand
undisturbed so that the impurities may settle down

on the surface of the container. In decantation,
water in the same container is poured into another
container without letting in the impurities. Sedimentation Decantation

F iltration
In the process of filtration, we use filter paper to separate the insoluble impurities

from water. In this process, water is passes through the filter paper leaving the
impurities behind. Water taps usually have filters inside them so as to give pure

water.

C hlorination

Water from rivers and lakes before supplying to our homes is purified by using to
kill the harmful germs. This process is called chlorination. It makes the water
safe for drinking.

S ave Water

We should not waste water because it is the most valuable natural resource. We
cannot think of life without water. Water is required for several purposes like

drinking, bathing, cooking, etc. There are many ways to save water.

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