Water : A Precious Resource
Class 7th Science NCERT Exemplar Solution
- Which of the following does not show water shortage?A. Taps running dry. B. Long queues…
- Seas and oceans are full of water on earth. However, a very small percentage of water…
- Which of the following are not the liquid forms of water? (i) Snow (ii) Lake water (iii)…
- A man digging the ground near a water body found that the soil was moist. As he kept…
- Which of the following is a way to use water economically?A. Construction of bawris B.…
- On which of the following day is World Water Day observed?A. 22 March B. 14 November C. 2…
- The amount of water recommended by the United Nations for drinking, washing, cooking and…
- “Every Drop Counts” is a slogan related toA. counting of drops of any liquid. B. counting…
- Water cycle does not involve which of the following?A. Evaporation B. Condensation C.…
- Which of the following inhibits the seepage of rainwater into the ground?A. A pukka floor…
- State whether the following statements are True or False. If false, write the correct…
- Some definitions are given below which can be corrected by changing one word. Correct…
- What is the source of water in each of the following? (a) Wells (b) Ground (c) Atmosphere…
- State whether the following statements are True or False. If false, give the correct…
- Fill in the blanks in the given passage. The rainwater and ________________ from other…
- Fill in the blanks and complete the story selecting words from the box given here. cold,…
- Place the following statements in a proper order to form a meaningful paragraph. (a) Which…
- How can you observe the three forms of water in (i) nature and (ii) at home?…
- Complete the given table
- Match Column I with Column II
- A list of jumbled words is given here. Write the correct form of each word. (a) WASHFERRET…
- From where do the following usually get water? In which form is water present in them? (a)…
Multiple Choice Questions
Question 1.Which of the following does not show water shortage?
A. Taps running dry.
B. Long queues for getting water.
C. Marches and protests for the demand of water.
D. A family gets three buckets of water per person per day.
Answer:
The amount of water available per person for proper hygiene and cooking is two and a half buckets per day. So, if a family gets three buckets of water per person per day, then it is fortunate and not under shortage of water. The other conditions like taps running dry, long queues for getting water and, marches and protests for the demand of water show shortage of water.
Question 2.
Seas and oceans are full of water on earth. However, a very small percentage of water present on earth is available for us. This percentage is roughly
A. 0.006%.
B. 0.06%.
C. 0.6%.
D. 6%.
Answer:
The total amount of fresh water available for use is about 0.006% of the total water present on earth.
Question 3.
Which of the following are not the liquid forms of water?
(i) Snow
(ii) Lake water
(iii) River water
(iv) Water vapour
(v) Ice
Choose the correct combination from the options below.
A. (i), (iv) and (v)
B. (i) and (ii)
C. (ii) and (iii)
D. (iv) only
Answer:
River and lake water are in liquid form. Snow is the solid form of water. Water vapour is a gaseous form of water. Ice is also a solid form of water.
Question 4.
A man digging the ground near a water body found that the soil was moist. As he kept digging deeper and deeper he reached a level where all the spaces between particles of soil and gaps between rocks were filled with water. The upper limit of this layer is called
A. water level.
B. water table.
C. groundwater.
D. water limit.
Answer:
The upper limit of the groundwater is known as the water table. As the man digs deeper, the level where all the spaces between particles of soil and gaps between rocks were filled with water is known as the water table.
Question 5.
Which of the following is a way to use water economically?
A. Construction of bawris
B. Rainwater harvesting
C. Drip irrigation
D. Infiltration
Answer:
Drip irrigation is used to water plants using narrow tubes to deliver water directly at the base of a plant.
The bawris are constructed to collect water for future use.
Rainwater harvesting is used to collect rainwater and use it in future.
Infiltration is the process of seeping of water into the ground.
Question 6.
On which of the following day is World Water Day observed?
A. 22 March
B. 14 November
C. 2 October
D. 21 December
Answer:
World Water Day is celebrated on 22 March.
Question 7.
The amount of water recommended by the United Nations for drinking, washing, cooking and maintaining proper hygiene per person per day is a minimum of
A. 5 litres
B. 15 litres
C. 30 litres
D. 50 litres
Answer:
The amount of water recommended by the United Nations for drinking, washing, cooking and maintaining proper hygiene per person per day is a minimum of 50 litres.
Question 8.
“Every Drop Counts” is a slogan related to
A. counting of drops of any liquid.
B. counting of water drops.
C. importance of water.
D. importance of counting.
Answer:
"Every Drop Counts" is a slogan related to the importance of water. It shows that every drop of water is precious and should not be wasted.
Question 9.
Water cycle does not involve which of the following?
A. Evaporation
B. Condensation
C. Formation of clouds
D. Rainwater harvesting
Answer:
Rainwater harvesting is a method used to recharge groundwater. It is used for conservation of water. All other options are stages of the water cycle.
Question 10.
Which of the following inhibits the seepage of rainwater into the ground?
A. A pukka floor
B. Playground
C. Grass Lawn
D. Forest land
Answer:
The seepage of rainwater into the ground cannot take place through a concrete floor or pukka floor. All other options involve the rainwater to fall on the soil. The water seeps through the soil to reach the water table.
Very Short Answer Questions
Question 1.State whether the following statements are True or False. If false, write the correct statement.
(a) Water vapour is the gaseous form of water.
(b) Ice is solid whereas snow is the semi-solid form of water.
(c) Ocean water cannot be used for domestic purposes.
(d) Rapid growth of industries is one of the causes for water shortage.
Answer:
(a) True
(b) False Both ice and snow are the solid forms of water.
(c) True
(d) True
Question 2.
Some definitions are given below which can be corrected by changing one word. Correct them.
(a) Aquifer is groundwater stored between layers of hard rock above the water table.
(b) The process of evaporation of water in the ground is called infiltration.
(c) The evaporation of water from oceans and its arrival back into oceans is called vapour cycle.
Answer:
(a) Aquifer is groundwater stored between layers of hard rock below the water table.
(b) The process of seepage of water in the ground is called infiltration.
(c) The evaporation of water from oceans and its arrival back into oceans is called water cycle.
Question 3.
What is the source of water in each of the following?
(a) Wells
(b) Ground
(c) Atmosphere
Answer:
(a) Groundwater and rainwater is the source of water in wells.
(b) The groundwater is recharged by rainwater seeped through the ground.
(c) The water vapours present in the atmosphere are due to evaporation of water from water bodies like rivers and oceans.
Question 4.
State whether the following statements are True or False. If false, give the correct statement.
(a) The process of seeping of water into ground is called filtration.
(b) 51% of the earth’s surface is covered with water.
(c) Year 2003 was observed as the International Year of Freshwater.
(d) Snow and ice both are solid forms of water.
Answer:
(a) False
The process of seeping of water into ground is called infiltration.
(b) False
71% of the earth’s surface is covered with water.
(c) True
(d) True
Short Answer Questions
Question 1.Fill in the blanks in the given passage.
The rainwater and ________________ from other sources such as rivers and ponds seeps through the ______________ and fills the empty spaces and cracks deep below the ground. The process of seeping of water into the ground is called ______________.
Answer:
The rainwater and water from other sources such as rivers and ponds seeps through the soil and fills the empty spaces and cracks deep below the ground. The process of seeping of water into the ground is called infiltration.
Question 2.
Fill in the blanks and complete the story selecting words from the box given here.
cold, demand, leaders, dry, hot, scarcity, workers,
wet, oceans, harvesting, rivers
Rajasthan is a _________ and dry place. The challenge of natural _______ of water was met by a successful experiment. A band of social ________ had transformed a _________ area into a green place. They have revived five dried-up ________ by constructing water ___________ structures.
Answer:
Rajasthan is a hot and dry place. The challenge of natural scarcity of water was met by a successful experiment. A band of social workers had transformed a dry area into a green place. They have revived five dried-up rivers by constructing water harvesting structures.
Question 3.
Place the following statements in a proper order to form a meaningful paragraph.
(a) Which in turn decreases the seepage of rainwater into the ground.
(b) This decreases the open areas like park, and playgrounds.
(c) Increasing population create demand for construction of houses, shops, offices, roads and pavements.
(d) This results in depletion of water table and creates scarcity of more water.
Answer:
(c ),(b),(a),(d)
Increasing population create demand for construction of houses, shops, offices, roads and pavements. This decreases the open areas like park, and playgrounds which in turn decreases the seepage of rainwater into the ground. This results in depletion of the water table and creates the scarcity of more water.
Question 4.
How can you observe the three forms of water in (i) nature and (ii) at home?
Answer:
(i) nature: The solid, liquid and gaseous form of water can be observed in nature as snow, lake water and water vapour present in the atmosphere.
(ii) at home: The solid, liquid and gaseous form of water can be observed in the home as ice, water in a bottle and water vapour from a kettle.
Question 5.
Complete the given table
Answer:
Question 6.
Match Column I with Column II
Answer:
Question 7.
A list of jumbled words is given here. Write the correct form of each word.
(a) WASHFERRET
(b) CHARREGE
(c) QUIFERA
(d) WOSN
Answer:
Question 8.
From where do the following usually get water? In which form is water present in them?
(a) Clouds
(b) Plants
(c) Mountaintops
(d) Aquifer
(e) Animals
Answer:
Long Answer Questions
Question 1.Complete the following chart by writing appropriate words in the boxes marked (a) to (e).
Answer:
Question 2.
What is groundwater? What are the sources of water which are fed by groundwater?
Answer:
If we dig deeper into the soil, then we would reach a depth where the soil-rock gap is filled by water. This is the upper layer and is called water table. The water found below the water table is called groundwater. It varies from place to place.
The sources of water that feed and are fed by groundwater are rivers, lakes and wetlands. The water in these sources come from the water below the water table.
Question 3.
Water is very precious for all the living beings. What will happen in future if we do not save water now?
Answer:
Water is essential for all the living beings. It is used for drinking, washing and cleaning. So, it is necessary to save water so that we do not run out of water in the future. if we do not save water now, the following things can happen:
● No construction work will be possible.
● Irrigation will be poor. Poor irrigation will lead to damage of crops. The plants will dry up if not watered for a few days.
● There will be no water present for industries.
● There will be draught and no water will be present for drinking purposes.