NCERT Exemplar Solutions Class 6 Science Water

Multiple Choice Questions (MCQs)

Question 1:  Which of the following activities does not involve use of water?

(a) Washing clothes   

(b) Bathing

(c) Cleaning utensils  

(d) Drying wet clothes

Solution 1:  The right thing for which selection is made is (d) Drying wet clothes. 

Wet clothing drying is an operation which does not require the use of water.

Question 2:  In which of the following activities will you use minimum amount of water?

(a) Bathing    

(b) Brushing teeth    

(c) Washing clothes  

(d) Mopping a room

Solution 2:  The right thing for which selection is made is (b) Brushing teeth.

We use a minimum amount of water while brushing our teeth.

Question 3:  The quantity of water required to produce one page of your book is

(a) one bucket  

(b) ten buckets  

(c) two glasses  

(d) few drops

Solution 3:  The right thing for which selection is made is (c) two glasses.

For the production of one page of our book, two glasses of water are needed.

Question 4:  Water in our tap comes from a

(a) river 

(b) lake  

(c) well  

(d) All of these

Solution 4: The right thing for which selection is made is (d) All of these. 

Water from the river, lake or well comes from our tap.

Question 5:  In which of the following cases, evaporation of water will be slowest?

(a) A tray of water kept in sunlight  

(b) A kettle of water kept on a burner

(c) A glass of water kept in a room    

(d) A bucket of water kept on rooftop

Solution 5:  The right thing for which selection is made is (c) A glass of water kept in a room.

The rate of evaporation increases as the temperature increases and as the surface area increases. In the options given, a glass of water held in a room has a minimum surface area, so the evaporation rate would be slowest.

Question 6:  Transpiration is a process in which plants

(a) receive water from soil        

(b) absorb water vapor from air

(c) prepare food from water      

(d) release water in the form of water vapor

Solution 6:  The right thing for which selection is made is (d) release water in the form of water vapor. 

Transpiration is a mechanism where water from plants is lost through the pores of their leaves as water vapor.

Question 7:  Clouds are

(a) tiny drops of water floating in air    

(b) mixture of dust and water vapor

(c) particles of water vapor      

(d) rain drops in air 

Solution 7:  The right thing for which selection is made is (a) tiny drops of water floating in air.

A cloud is called the mass of tiny droplets produced by the water vapor condensation which we see floating high in the atmosphere.

Question 8:  Wells are fed by:

(a) pond water    

(b) lake water

(c) rainwater      

(d) groundwater 

Solution 8: The right thing for which selection is made is (d) groundwater.

Wells are groundwater-fed. By drilling a well into the field, the underground water may be taken out. It is named the water well.

Question 9:  Floods caused extensive damage to

(a) crops                          

(b) property and human life

(c) domestic animals        

(d) All of these

Solution 9:  The right thing for which selection is made is (d) All of these.

Floods have caused extensive damage to fields, villages and forests, resulting in damage to land, human life, domestic animals, crops and forest wildlife.

Question 10:  ‘Catch water where it falls’ is the basic idea behind

(a) recycling of water       

(b) making dams to store water

(c) rainwater harvesting  

(d) condensation of water vapor

Solution 10:  The right thing for which selection is made is (c) rainwater harvesting.

The basic principle behind rainwater harvesting is 'Collect water where it falls.'

Very Short Answer Type Questions

Question 11:  Look at the figure:

Write down the activities shown in this figure in which water is being used.

Solution 11:  The activities shown in the figure given above are:

(i) Washing clothes.

(ii) Bathing.

Question 12:  Write any two activities which require more than a bucket of water.

Solution 12:   Washing more than 10 garments and irrigating a crop field are two tasks that involve the use of more than one bucket of water. 

Question 13: Write any two activities which require less than one bucket of water.

Solution 13:  Brushing teeth and washing a handkerchief are two operations that involve less than one bucket of water to be used.

Short Answer Type Questions

Question 14:  Why do wet clothes placed on a clothes line dry after sometime? Explain.

Solution 14:   After some time, wet clothes put on a clothes line dry because water in wet clothes is transformed into water vapor and released into the atmosphere because of evaporation that leaves them dry.

Question 15:  Water kept in sunlight gets heat from the sun and is evaporated. But how does water kept under the shade of a tree also gets evaporated? Explain.

Solution 15:  Water kept under a tree's shade often evaporates due to the warm weather. In reality, the heat generated by the sun heats all the air around us during the daytime. This warm air provides fuel for water kept in the shade to evaporate.

Question 16:  How do the areas covered with concrete affect the availability of groundwater?

Solution 16:   The availability of groundwater is influenced by areas paved with concrete because concrete limits the runoff of rainwater into the field, contributing to a decrease in groundwater availability.

Question 17:  Why is there a need for conserving water? Give two reasons.

Solution 17:   There is a need for water conservation for the following reasons:

i)        More demand for available water is being created by a growing population.

ii)       Day-to-day freshwater supply is declining.

Question 18:  Fill in the blanks.

Water, as ……… goes into atmosphere by the processes of ………. and ………. and forms ………. which on condensation fall in the form of ……… and ……… .

Solution 18:   vapors, evaporation, transpiration, clouds, rains, snow/hails.

Long Answer Type Questions

Question 19:  Most of the water that falls on the land as rain and snow, sooner or later goes back to a sea or an ocean. Explain how it happens.

Solution 19:   The mechanism by which groundwater returns to the sea or ocean is as follows:

i)        In the form of streams and rivers, snow/rain falling on the mountains melts into water that flows down.

ii)       In the form of streams or rivers, a portion of the rainwater is absorbed into the soil and the remainder flow.

iii)     After flowing through multiple areas, the river water eventually enters the sea or ocean.

Question 20:  Draw a diagram to show how sea water reaches a lake or pond?

Solution 20:   A diagram is represented by sea water reaching a lake or pond:

Question 21:  Dissolve two spoons of common salt in half a cup of water. Now, if you want to get the salt back, what will you do?

Solution 21:   By extracting the water from the salt solution, the common salt dissolved in half a cup of water can be recycled.

This can be accomplished by heating the solution on a gas stove or leaving it on a plate for a few hours under the sun.

We would get the salt back because of the evaporation of water in both systems.

Question 22:  Explain the process of rooftop rainwater harvesting with the help of a suitable diagram.

Solution 22:   The process of harvesting rainwater from rooftops is as follows:

i)        In this process, on the rooftop, rainwater is collected.

ii)       The rainwater that was collected was able to pass through pipes into a storage tank at ground level.

The water collected is filtered and, where required, used.