1. Answer the following questions
(i) What is precipitation?
Ans. Precipitation is the deposition of moisture from the atmosphere onto the earth’s surface. This may be in form of rain, hail, frost, fog, sleet or snow.
(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 the water cycle.
(iii) What are the factors affecting the height of the waves?
Ans. Factors affecting the height of the waves are :-
- High speed of wind
- Earthquake
- Volcanic Eruption
- Underwater Landslides
(iv) Which factors affect the movement of ocean water?
Ans. (a) Temperature and (b) Rotation of the earth.
(v) What are tides and how are they caused?
Ans. The rhythmic rise and fall of ocean water twice a day is called a tide. Tides are caused due to the gravitational pull exerted by the sun and the moon on the earth’s surface.
(vi) What are ocean currents?
Ans. Ocean currents are streams of water flowing constantly on the ocean surface in definite directions.
2. Give reasons.
(i) Ocean water is salty.
Ans. Because it contains large amounts of dissolved salts.
(ii) The quality of water is deteriorating.
Ans. The quality of water is deteriorating because:
- Garbage in thrown in the river
- Chemicals from industries are polluting the water
- Remains of the harmful insecticides and pesticides are flowing from the fields towards the river
- Unburnt or half burnt corpses of human and animals are thrown in water bodies
3. Tick the correct answer.
(i) The process by which water continually changes its form and circulates between oceans, atmosphere and land
(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 currents (c) waves
4. Match the following.
(i) Caspian Sea
Largest lake
(ii) Tide
Periodic rise and fall of water
(iii) Tsunami
Strong seismic waves
(iv) Ocean currents
Streams of water moving in definite paths