Page 70 - Science class 4

1. Boiling

It is the simplest way to purify water. Boiling water for at least 10–15
minutes kills the germs in it. Boiled water should be stored in clean and
covered pots or bottles.

2. Sedimentation or Decantation

It is another way of purifying water. In this process, water is allowed to
stand in big containers, without being touched, for a few hours. All the

mud and insoluble impurities settle at the bottom of the container. This
process in which the insolubles settle down is called sedimentation.

Next, water is poured out very gently, without disturbing the settled
impurities.
3. Filtration

It is a better process than decantation for purifing water. In this process,

water is passed through a filter paper. The impurities are left behind on
the filter paper and clean water is collected below. This process of
cleaning water by passing it through filter paper is called filtration.

4. Adding Chlorine

Adding chlorine gas kills germs. Nowadays, chlorine tablets are easily
available. Adding chlorine tablets to water kills germs and makes the

water pure. This process is called chlorination .

Tips
Tips
Tips to handle waterto handle waterto handle water
± Do not waste water. Water is very
precious.

± Store water in a clean place and in a
clean pot. Keep drinking water covered.

± Never keep drinking water near bins

and drains.
± Clean the storage pots and utensils

regularly before filling them with water.

± Tap water should be boiled before using it for drinking purposes. You

could even use chlorine tablets to kill germs.

± Water storage tanks should be cleaned from time to time.
USES
USES OF WATER
USES OF WATER OF WATER
Water is very important for us. It is useful to us in many ways.