NCERT Book Class 7 Social Science (Geography) Chapter 5 Water

5 Water
Glossary When you think of water, what images come to your
mind? You think of rivers, the waterfalls, the pitter patter
Terrarium: It is an of raindrops, water in your taps... Children love to float
artificial enclosure for paper boats in rain puddles. By noon the puddles vanish.
keeping small house Where does the water go?
plants. 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
Activity
sea in the form of rain, snow or sleet.
Make your own The process by which water continually changes its
Terrarium form and circulates between oceans,
atmosphere and land is known
as the water cycle (Fig 5.1).
Our earth is like a
terrarium. The same water Condensation
that existed centuries ago
still exists today. The Precipitation
A Terrarium
water used to irrigate a
field in Haryana may
Fill one-fourth of a big
jar with soil and have flowed down the
press it well. Put a Amazon River a
thin layer of humus hundred years ago.
on top of it. Plant the The major sources
largest plants first of fresh water are the
and then arrange the rivers, ponds, Run off
smaller ones around springs and
them. Spray the Evaporation
glaciers. The
arrangement with
ocean bodies and
water and close the
jar. The water that the seas contain
evaporates from the salty water. The
leaves and soil water of the
condenses and falls oceans is salty or
back in the form of saline as it
drops of water. contains large Fig. 5.1: Water Cycle