CBSE Class 7 Science Water A Precious Resource Worksheet

Question. The upper level of ground water is called
(a) Ground level
(b) water level
(c) ground table
(d) water table

Answer : C

Question. Which of the following water is unfit for human consumption?
(a) Sea water
(b) surface water
(c) ground water
(d) well water

Answer : A

Question. Which of the following has ground water as its source.
(a)Tube well
(b) hand-pump
(c) well!
(d) all of these

Answer : D

Question. Nearly 71% of the earth's surface is covered with 
(a) Air
(b) water
(c) soil
(d) ice

Answer : B

FILL IN THE BLANKS :

Question. ___ is celebrated as World Water Day eveli year.

Answer : 22ndl march

Question. Snow and ice are __ form of water.

Answer : Solid

Question. The process of seeping water into the ground is called ___

Answer : Percolation 

Question. ___ is a step-well in which rain water is collected and stored.

Answer : Bawri

VERY SHORT ANSWERS TYPE QUESTIONS :

Question. What is meant by water table?
Answer : The upper level of ground water is called water table.

Question. What is the minimum water requirement per person per day for various basic needs?
Answer : 50 litres

Question. Name the (a) solid form of water and (b) gaseous form of water.
Answer : (a) ice and (b) vapour

Question. Which type of irrigation practice can help in conservation of water?
Answer : Drip irrigation

SHORT ANSWERS TYPE QUESTIONS :

Question. What are aquifers?
Answer : The collection of groundwater inside the earth, between the layers of hard rocks below the water table, is called aquifer.

Question. Name three factors that deplete the water table at a place.
Answer : 1. Increase in water
2. Deforestation-cutting down a large number of trees
3. Increase in industries.

Question. Most of the water ava~lable on the earth is unfit for human consumption. Why?
Answer : Most of the water available on earth's surface is present in the sea and ocean. This water is salty and cannot be consumed directly and therefore is unfit for human consumption.

Question. Define natural resource.
Answer : Any component of the earth or environment that can be utilised by human beings to fulfil their needs is known as natural resource.

Question. Why are bawris being revived?
Answer : Bawri is a step-well in which the rainwater is collected and stored. It provides water to the people during drought period.

SHORT ANSWERS TYPE QUESTIONS :

Question. What is meant by 'rainwater harvesting'? give two advantages of rainwater harvesting.
Answer : the process of collecting rainwater from roof and street corners and storing it for later use is called rainwater harvesting. It may be advantageous due to the following reason:
1. The water table can be raised by rainwater harvesting.
2. It reduces the run off loss of rainwater.

Question. Define water cycle. Name the processes involved in water cycle.
Ans. the continuous movement of water from the earth's surface and water bodies as water V8JPOur to the atmosphere and from the atmosphere back to the earth's surface as rain, hail, and snow is called water cycle.
The processes involved in water cycle are evaporation , condensation, and precipitation.

Question. What are the effects of water scarcity?
Answer : 1. Non-availability of food
2.Non-availability of oxygen
3. Less rainfall

Question. How can we save water at home? Give any five ways.
Answer : 1. Close water taps when not in use.
2.repair any leakage from pipes
3. after washing clothes reuse the water for floor cleaning or watering plants.
4. instead of shower use bucket for bath or other purposes.
5. take as much water you need, don't through remaining water after drinking.

LONG ANSWER TYPE QUESTIONS :

Question. Explain the factors that deplete the water table at a place.
Answer : The factors responsible for the depletion of water table are:
1. Increase in population- To meet the needs of an ever increasing human population, water is utilised, resulting in the decrease in water table.
2. Increase in industries- the number of industries is increasing continuously that draws a huge amount of water from the ground leading to the depletion of water table.
3. Deforestation- cutting down of trees make the soil loose that fails to hold sufficient quantity of water under the soil.
4. Decrease in the effective area for seepage of water- the increasing demand for construction of houses, shops, offices, roads, cemented floor has decreased the open area and does not allow water to seep in the ground. This also depletes the water table.
5. Scanty rainfall- insufficient rainfall also leads to the depletion of water table.
6. Increase in agricultural activities- with the increase in population, demand for food also increases. Because of unpredictable rain the farmers are bound to depend on the irrigation system and to utilise groundwater. this leads to the decrease in water table.

Question. Discuss various ways for proper management of water.
Answer : Steps that can be taken for management of water are as follows:
1. Rain water harvesting- to overcome the shortage of water the ra in water can be stored and used.
2. Prevention of wastage of water- household usage of water should be reduced.
3. Revival of Bawris- bawris are step-well, which can be used to store rain water for future use.
4. Drip irrigation system- drip irrigation technique deliver water drop by drop to the roots of the plant, and thus prevent wastage of water.

HOTS QUESTIONS :

Question. Why is making of tube well is prohibited in residential areas?
Answer : making of tube well is prohibited in residential areas because it loosens the soil layers are and subsides the land. It also lowers the water table and thus local resident will feel difficulty in the supply of water.

Question. Why is distribution of water uneven in our country?
Answer : The distribution of rainfall uneven in India due to the following reasons: Latitudinal extent: The tropical and coastal regions and plains receive more rainfall than the plateau and desert regions in the interior.
Relief and topography: The windward side of mountains and hills receive more rainfall than leeward side.