SCIENCE Chapter 16: Water

 SCIENCE  Chapter 16: Water

1. Fill in the blanks: (R)

a) The roots of plants and trees retain significant amount of water in the soil that

increases the groundwater.

b) The scarcity of water leads towards the desertification of landscapes.

c) Rainwater can get polluted while falling on the Earth due to air pollution.

2. State whether the following statements are true or false. Correct the false

statements: (U)

a) Large scale planting of trees is called afforestation. True

b) Paper products such as old newspapers, magazines, books and notebooks

should not be recycled.

False

Paper products such as old newspapers, magazines, books and

notebooks should be recycled.

c) Sanitation becomes a bigger problem due to scarcity of water.

True

3. Assertion-Reason type questions: (An)

In the following questions, two statements Assertion (A) and the other labelled

Reason (R). Read the statements carefully and choose the correct alternative (A),

(B), (C) and (D) as given below.

(A) Both A and R are true and R is the correct explanation of the Assertion.

(B) Both A and R are true but R is not the correct explanation of the Assertion.

(C) A is true but the R is false.

(D) A is false but R is true.

a) Assertion: Ground water is the major source of drinking water in both

urban and rural India.

Reason: Ground water is accessible through tube wells and hand-pumps.

Ans: (A) Both A and R are true and the R is a correct explanation of

the Assertion.

b) Assertion: Lower rainfall is a cause for depletion of water resources.

Reason: Water resources are recharged by rain water.

Ans: (A) Both A and R are true and the R is a correct explanation of

the Assertion.

4. Define the following: (R)

a) Infiltration: The process of seepage of water through the soil

is known as infiltration.

b) Boiling point: The temperature at which a liquid gets

converted into a gas is called boiling point.

5. Answer the following questions in detail: (U)

a) How can government create awareness about effective water

management?

 The government with NGOs should organise effective

campaigns to make people aware about the importance

of water.

 This awareness should reach all levels of

the society especially children.

 In order to shun depletion of water, each individual should be

taught to reuse, recycle and reduce the wastage of water.

b) How does water scarcity lead to loss of habitat and destruction of

ecosystem?

 The natural landscapes are affected severely because of the

scarcity of water.

 The scarcity of water leads towards the desertification of

landscapes; death of the plants and destruction of wildlife.

 Consequently, an entire ecosystem of a region collapses and

food shortages become a permanent problem. As a result,

various animals lose their natural habitat.

6. Observe the picture and answer the questions that follow: (Ap)

a) Name the above water management technique.

Ans: Rainwater harvesting/water harvesting

b) How can we use the water collected by this technique? (Give any two points)

Ans: Water can be used for daily activities. It can also be used to

recharge the local aquifers.

7. Read the situation given in the paragraph and answer the questions that

follow: (An)

Mr Shelar attended a water awareness program. He learnt that although 71%

of the earth is covered with water only 2.5% is fresh water. Out of this fresh

water, about 79% is frozen in glaciers, about 20% is found in ground water

and only 1% is available on the surface in lakes, ponds and rivers. He also

found that some factors such as lower rainfall, water pollution, inefficient

methods of irrigation, overuse of ground water are depleting water resources

and the world is facing water scarcity.

a) List two factors given in the paragraph which are responsible for depletion of

water resources.

Ans: lower rainfall, water pollution, inefficient methods of irrigation, overuse

of ground water. (accept any two)

b) From the above passage can we conclude that only 21% of the fresh water on the

earth is available for use? Justify your answer.

Ans: Yes we can conclude this from the paragraph because 79% of the fresh

water is frozen in glaciers and unavailable for use.

8. Unscramble the words. (U)

1. TNOAENICDSNO CONDENSATION

2. STSEOCYME ECOSYSTEM

3. SCLEGLRI GLACIERS

4. GIEPRSLENHNI REPLENISHING

9. Higher Order Thinking Skills (HOTS) (U)

If ground water reaches the surface, how does it reenter the water cycle?

Ans: It reenters the water cycle by evaporation into the earth’s atmosphere.