NCERT Solutions Class 7 Social Science Chapter 5 Water

NCERT Solutions for Class 7 for Social Science Geography Chapter 5 Water

1. Answer the following questions: 

(i) What is precipitation? 

Ans. The process of water falling back to the surface of the earth from the atmosphere in any form is known as precipitation. 

(ii) What is water cycle? 

Ans. The process by which water continually changes its form and circulates between oceans, atmosphere, and land is known as water cycle. 

(iii) What are the factors affecting the height of the waves? 

Ans. The factors affecting the height of the waves are: 

(a) Speed of wind 

(b) Gravitational pull of the moon 

(c) Underwater volcanic eruption, etc. 

(iv) Which factors affect the movement of ocean water? 

Ans. The factors affecting the movement of ocean water are: 

(a) Temperature

(b) Rotation of the earth 

(v) What are tides and how are they caused? 

Ans. The rhythmic rise and fall of ocean water twice in a day are known as tides. They are caused by the strong gravitational pull of the sun and the moon. 

(vi) What are ocean currents? 

Ans. The streams of water flowing constantly on the surface of the ocean in definite directions are known as ocean currents. 

2. Give reasons. 

(i) Ocean water is salty. 

Ans. The rivers flowing into the oceans carry many dissolved minerals and salts along with it. When water evaporates, all the dissolved minerals and salt are left behind in the water making it salty. The salt present in ocean water is mainly sodium chloride. 

(ii) The quality of water is deteriorating. 

Ans. Almost three-fourth of our earth is covered with water, yet only 3% of this is fresh water, which can be used by us. The amount of fresh water remains constant but the population is rapidly increasing. To meet the requirements of this increasing population, we are overusing and polluting the existing sources of water. Factors like deforestation, industrial and agricultural pollution of rivers and lakes, wastage of water, pollution of ground water, etc., are responsible for the deteriorating quality of water today. 

3. Tick the correct answer. 

(i) The process by which water continually changes its form and circulates between oceans, atmosphere, and land is called: 

(a) Water cycle        (b) Tides         (c) Ocean currents 

(ii) Generally the warm ocean currents originate near: 

(a) Poles                  (b) Equator       (c) None of these 

(iii) The rhythmic rise and fall of ocean water twice in a day is called: 

(a) Tide                (b) Ocean current    (c) Wave  

4. Match the following: 

(i) Caspian Sea        (a) Largest lake 

(ii) Tide                    (b) Periodic rise and fall of water 

(iii) Tsunami            (c) Strong seismic waves 

(iv) Ocean currents (d) Streams of water moving along definite paths 

                              (e) Water cycle 

Ans. 

(i) Caspian Sea        (a) Largest lake 

(ii) Tide                   (b) Periodic rise and fall of water 

(iii) Tsunami            (c) Strong seismic waves 

(iv) Ocean currents  (d) Streams of water moving along definite paths