Class 7 Water A Precious Resource
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Water A Precious Resource
KEYWORDS
Precipitation: The water which falls from the clouds as rain or snow.
Groundwater: The reservoir of water collected above impervious rocks below the earth’s surface.
Permeable rocks: Rocks which allows water to pass through it.
Impermeable rocks: Rocks which does not allow water to pass through it.
Infiltration: The process of seeping of water into the ground is called Infiltration.
Water table: The upper limit of the groundwater.
Scanty rainfall: insufficient rainfall
Rainwater harvesting: The process of collecting rainwater from roofs, street corners, etc, and storing it for later use.
POINTS TO REMEMBER
• Water is important for sustaining life and acts as a media for a variety of life processes.
• Water exists in three physical states i.e., solid, liquid and gas and these are interchangeable.
• Rivers, lakes, tanks and ponds are surface water sources.
• The water which falls from the clouds as rain or snow is called precipitation.
• The process of seeping of water into the ground is called Infiltration.
• The water stored in impervious rocks is called groundwater.
• The reservoir of water above impervious rocks below the earth’s surface is called groundwater. The upper limit of the groundwater is called the water table.
• When there is more rainfall and more rainwater seeps into the ground, the water table rises and vice versa if an excessive amount of groundwater is withdrawn for domestic, irrigation and industrial use then water table falls.
• Some of the factors which affect the water table at a place and make it go down are: Increase in population, increase in industries, increase in agricultural activities, deforestation, scanty rainfall etc.
• India is a vast country and the rainfall is not the same everywhere. Some regions of India have excessive rainfall whereas some other regions of India have little rainfall.
• One way of increasing the availability of water to overcome shortage is rainwater harvesting.
• Bawri is a step-well in which the rainwater is collected and stored to provide a supply water to the people during drought periods. Nowadays due to the acute water shortage faced by the people in some places, the barriers are being renovated and revived.
• Drip irrigation is a technique of watering plants by making use of a system of narrow pipes or tubes with small holes which deliver the water drop by drop directly around the roots of the plants.
• Rainwater or river water can be prevented from flowing away by constructing dams. The dams prevent floods, provide water for irrigation and for many other uses.
Exercises on Water A Precious Resource
Multiple Choice Questions (MCQs)
1. Water fit for human consumption is
(a) rainwater
(b) potable water
(c) saline water
(d) distilled water
2. The chief source of water supply for agriculture needs is
(a) groundwater
(b) surface water
(c) rainwater
(d) all
3. Water table goes down due to:
(a) The increase in industrialisation
(b) The increase in pollution
(c) The increase in the agriculture area
(d) All of the above
4. Which of the following is not responsible for water shortage?
(a) The rapid growth of industries
(b) The increase in population
(c) heavy rainfall
(d) Mismanagement of water resources
5. The total water
(a) in the lakes and rivers of the world remains constant
(b) under the ground remains constant
(c) In the sea and oceans of the world remains constant
(d) of the world remains constant
6. The minimum amount of water recommended by the United Nations
per person per day is:
(a) 25 L
(b) 50 L
(c) 75 L
(d) 40 L
7. Water which falls from the clouds as rain or snow is called
(a) condensation
(b) precipitation
(c) infiltration
(d) transpiration
8. What percentage of earth’s surface is covered with water?
(a) about 51%
(b) about 21%
(c) about 71%
(d) about 81%
9. Which of the following does not deplete the water table at a place?
(a) increasing number of tube-wells
(b) increasing deforestation
(c) scanty rainfall
(d) the increase in snowfall
Multiple Choice Questions (MCQs)
1. (b) 2. (c) 3. (d) 4. (c) 5. (d) 6. (b) 7. (b) 8. (c) 9. (d)
Fill in the blanks:
(a) Three forms of water are,———- and———–
(b) The process of water seepage into the ground is called————–.
(c) Bari was the traditional way of collecting———-.
(d) The rainwater can be used to——— the groundwater.
(e) The best way to overcome the shortage of water is——————.
Answers:
Fill in the blanks:
(a) Three forms of water are liquid, solid and vapour.
(b) The process of water seepage into the ground is called infiltration.
(c) Bawri was the traditional way of collecting water.
(d) The rainwater can be used replenish the groundwater.
(e) The best way to overcome the shortage of water is Prevention of wastage of water.
State whether True (T) & False (F):
(a) Saline water is not fit for drinking.
(b) Water cycle provides an abundant supply of fresh water.
(c) The water table is constant at every place on the earth.
(d) Rain is the ultimate source of water.
(e) The water-bearing layer of the earth is called water table.
Answers:
(a) T (b) T (c) F (d) T (e) T