Kerala scert water chapter

1. WATER AND GASES

3. ■ What do you observe in this picture?
Aquarium
■ Which gas do creatures use for breathing?
Oxygen
■ Which gas is used by plants produce food?
Carbon dioxide
■ How do aquatic creatures and aquatic plants get oxygen
to breathe?
Oxygen that dissolved in water

6. ■ Why is air continuously introduced in to the water in
aquarium?
To increase dissolved oxygen in the water
■ Is there any problem the amount of oxygen decreases?
Yes
■ How can reduce this?
By continuously passing air
■ We give fish food to fishes when the amount of food
increases what happened?
Fishes in the tank will die

7. ■ What is the reason?
When food is decomposed using the oxygen
present in water. So the presence of oxygen in water
decreases
■ When the amount of oxygen decreases in water.what
happens to the water?
Water gets polluted
■ How water get polluted in other ways?
Dumping wastes in water

8. ■ How the polluted water affect the aquatic creatures?
It destruct the life of aquatic creatures

9. Aquatic animals and plants make use of the
oxygen dissolved in water.. Water gets
polluted as the amount of oxygen in it
decreases.

13. ■ What do you observe in the pictures?
Water pollution
■ Who is responsible for this pollutions?
Human beings
■ What are the causes of water pollution ?
Dumping of wastes in water resources
Rampant use of fertilizers
Excessive use of detergents
Insecticides getting mixed with water

14. ■ What are the effects of water pollution?
Deaths of aquatic creatures, destruction of food
chains, diseases.
■ What are the possible remedies to avoid water
pollution?
Don’t throw wastes in to water
Use waste bins
Decrease the use of pesticides

15. The wastes dumped in to rivers and ponds
decay using the oxygen dissolved in them.
This depletes the amount of oxygen and
results in the destruction of aquatic life.

16. Find the answer
■ Which gas do creatures use for breathing?
Oxygen
■ Which gas is used by plants produced food?
Carbon dioxide
■ .............. And carbon dioxide dissolved in water?
Oxygen
■ During the photosynthesis which gas is emitted?
Oxygen

17. ■ How the aquatic animals and plants get oxygen and
carbon dioxide?
■ What happens acquatic creatures when wastes
dumped in water?

18. Assignment
■ List various activities that cause water pollution
■ Prepare a note on methods to be adopted to prevent
water pollution