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SAI INTERNATIONAL SCHOOL
Class-6

Lesson Notes
Subject-Physics
Ch.- Water: The Life-giving Liquid
Subtopic- Sources of Water

Sources of water:
Rain water:
 The main source of water is rain.
 Rainfall occurs when the water vapour in the air condenses.
 Rainwater is considered purest form of water. But, while falling down in the
atmosphere, it gets mixed with dust particles and other impurities present in
the atmosphere and becomes polluted.

Ground water:
 During rainfall, a part of the rainwater percolates through ground and forms
groundwater.
 Water passes through the several layers of rocks and sand, it gets naturally
filtered and is free form suspended impurities.
 Approximately, 30% of the total fresh water found on the earth exist as
groundwater.
 We can obtain groundwater by digging Wells and tube wells.