STD-4: CHAPTER-9: METHODS OF SAFE-HANDLING OF WATER: EXTRA QUESTION-ANSWERS

 1.      Why does our body need water?

Ans: i) Water is needed for proper functioning of our body.

ii) Our body needs water for digestion of food and for removal of wastes from the body.

2.      We need to drink _______ glasses of water everyday.

Ans: We need to drink eight to ten glasses of water everyday.

3.      Define potable water.

Ans: Water, which is clean and fit for drinking, is called potable water.

4.      State two methods of drawing ground water.

Ans: Ground water can be drawn from wells or by using hand pumps.

5.      What are germs?

Ans: Germs are extremely small living beings which can cause diseases.

6.      Name the diseases that can be caused by drinking unclean water.

Ans: Jaundice, diarrhea, dysentery and cholera can be caused by drinking unclean water.

7.      Why should water be purified before drinking?

Ans: Drinking unclean water can cause diseases, as they contain dirt and germs. So, water should be purified before drinking.

8.      State three methods of purifying water.

Ans: Three methods to purify water are, i) Boiling,  ii) Filtration,  iii) Chlorination

9.      How does boiling help in making water safer for drinking?

Ans: Boiling kills the germs present in water. Thus, boiling helps in making water safer for drinking.

10.  What is filtration?

Ans: Filtration is a method for removing dust and other suspended particles from water.

11.  How can traditionally water be purified?

Ans:i) We can filter water through a clean, thin cloth.

ii) We can also use a traditional filter containing sand and gravel.

12.  How filtration method is useful?

Ans: Filtration removes dust and other suspended particles from water.

13.  What is drawback (demerit) of filtration method?

Ans: Filtration method does not remove germs.

14.  Why is the traditional method of filtration not completely sufficient for making water fit for drinking?

Ans: i) Traditional method of filtration removes dust and other suspended particles from water.

ii) But, this method does not remove germs.

So, traditional method of filtration is not completely sufficient for making water fit for drinking.

15.  What is the difference between traditional filters and modern filters?

(OR) How modern filters are more useful than traditional filters?

(OR) What is the advantage of modern filters over traditional filters?

       Ans: i) Traditional filters does not remove germs. For removing germs, water should be boiled after filtration.

ii) But, modern filters remove germs along with dirt and dust. Water filtered by such filters can be directly used for drinking.

So, modern filters are more useful than traditional filters.

16.  What is chlorination? How does it purify water?

Ans: i) Adding a correct small amount of chlorine in filtered water, is called chlorination.

ii) Chlorination kills germs and makes it fit for drinking.

17.  What is stagnant water?

Ans: Standing water or still water is called as stagnant water.

18.  Why should we not allow water to stagnate around our houses?

Ans: i) Dirty and stagnant water is a major cause of diseases.

ii) Stagnant water is a breeding place for mosquitoes.

So, we should not allow water to stagnate around our houses.

19.  Name some places where water can stagnate.

Ans: Water can stagnate in old or broken containers, in room coolers, in flower pots etc.

20.  Name the diseases which are spread by mosquitoes.

Ans: Malaria, dengue and chikungunya are spread by mosquitoes.

21.  State two ways that can be used to prevent breeding of mosquitoes in room coolers.

Ans: We can adopt the following measures to prevent the breeding of mosquitoes in room coolers,        i) We should change water in room coolers after every 3-4 days.

ii) When water in room coolers cannot be changed, two spoons of kerosene should be put in it.

22.  Which substances are used for making containers of water?

Ans: Copper, brass, steel and plastics are used for making water containers.

23.  Why proper storage and safe handling of water is important?

Ans: Proper storage, and safe handling, of purified water is very important to keep the germs away.

24.  State the ways of safe handling of drinking water.

Ans: Some ways of proper storage and safe handling of water are,

i) Water should always be stored in clean and covered containers.

ii) We should never dip our hands in water stored for drinking purpose.

iii) We should use a ‘ladle’, or some other clean utensil, to take out water from a container.

iv) We should not drink water that has been stored for many days.