Water Class 7 Social science ( Geography ) NCERT Solution CBSE

1. WATER
◦Rivers, the waterfalls, raindrops,
water in your taps.
◦Childrens love to float paper
boats in rain puddles.
◦A liquid amount of water,
especially the water in a lake
river or sea.

2. ◦The sun’s heat causes evaporation of water
into vapour.
◦When the water vapour cools down, it
condenses and forms clouds.
◦From there it may fall on the land or sea in
the form of rain, snow or sleet.

3. Water cycle

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

5. ◦The major sources of fresh water are the rivers, ponds,
springs and glaciers.
◦The ocean bodies and the seas contain salty water.
◦The water of the oceans is salty or saline as it contains large
amount of dissolved salts.
◦Most of the salt is sodium chloride or the common table salt
that you eat.

6. WORLD- MAJOR SEAS,LAKES ANDRIVERS

7. Distribution of Water Bodies
◦ The distribution of water in percentage:
oceans : 97.3
Ice- caps : 02.0
Ground water : 0.68
Fresh water Lakes : 0.009
Inland seas and salt lakes : 0.009
Atmosphere : 0.0019
Rivers : 0.0001
100.00

8. Ocean Circulation
◦ Ocean Circulation is the large scale movement of water in the ocean basins.

9. ◦ The water of the oceans is not calm like that of ponds or lakes or other
such bodies. It is always in a state of movement. It circulates in various
directions, following different patterns under different forces. These
movement are categorized as waves, current, and tides.
◦ It is a key regulator of climate by storing and transporting heat, carbon,
nutrients and fresh water all around the world.
◦ The wet sand on the beach, the cool breeze, the sea bird, the smell of the
salt in the air and music of the waves; everything is so fascinating.

10. WAVES

11. Whenthewateronthesurfaceoftheoceanrisesandfalls
alternatetheyarecalledwaves.
Wavestravelataspeedofmorethan700kmperhour.
Wavesaregenerallycausedbytheactionofwindsonthe
surfaceofoceanwater.

12. TIDES

13. The rhythmic rise and fall of ocean water twice in a day is called a
tides. It is high tide when water covers much of the shore by
rising to its highest level. It is low tide when water falls to its
lowest level and recedes from the shore. The strong gravitational
pull exerted by a sun and the moon on the earth’s surface causes
the tides. Tides are very long-period waves that move through
the ocean in response to the forces exerted by the moon and the
sun.

14. OCEAN CURRENTS
Ocean Currents are streams of water flowing constantly on the ocean
surface in definite direction. The ocean current may be warm or cold.
The Labrador ocean current is cold current while the gulf stream is a
warm current. The areas were the warm and the cold currents meets
provide the best fishing grounds and also experience foggy weather of
the world. Seas around Japan and the Easthern coast of North America
are such example.