Class-6 Science, Chapter-14 Water, Additional exercises with solutions in line with NCERT book / CBSE Syllabus
Chapter 14
Water
=========================================================
Exercises from
textbook
Additional
Exercises
Tables from
Textbook
Activities/Projects
Additional Exercises
Choose the correct answer:
1-
More and more water is
being used for
a.
Industries
b.
Agriculture
c.
Domestic purposes
d.
All the above (√)
2-
‘Çatch water where it
falls’ is the basic idea behind
a.
Draught
b.
Flood
c.
Rainwater harvesting
(√)
d.
Transpiration
3-
The release of water
by plants into the atmosphere occurs through a process called
a.
Evaporation
b.
Transpiration (√)
c.
Vaporization
d.
None of the above
4-
The rainwater that
seeps into the soil is recharges
a.
Ground water (√)
b.
Rainwater
c.
Floodwater
d.
Distilled water
5-
Excessive rains may
cause
a.
Draught
b.
Flood (√)
c.
Evaporation
d.
All the above
6-
Lack of water for long
periods may cause
a.
Draught (√)
b.
Flood
c.
Evaporation
d.
All the above
7-
Many tiny droplets of
water come together and fall down as
a.
Rain
b.
Hail
c.
Snow
d.
All the above (√)
Fill in the blanks with suitable words:
1-
Two third of the Earth
is covered with water.
2-
The sea water is saline.
3-
Heating is essential
to convert water into its vapours.
4-
Tiny droplets of water
that remain floating in air , appear to us as cloud.
5-
Sowing of many crops
depends on the arrival of monsoon.
6-
Draught
happens if it doesn’t
rain in a region for a year or two.
State whether the following statements are True or False:
1-
To obtain salt, water
from the sea is left in shallow pits to let the water evaporate.True
2-
There has been a loss
of ground water due to overuse. True
3-
In our country, most
of the rainfall occurs during the monsoon season. True
4-
Floods cause extensive
damage to crops, domestic animals, property and human life. True
5-
Water present in
oceans can be used directly. False
6-
The number of people
using water is decreasing with rising population. False
Give one word for the following:
1-
The process through
which water vapour gets transferred into air.
2-
Ans- Evaporation
3-
The process through
which water is released by the plants into air.
4-
Ans- Transpiration
5-
The circulation of
water between oceans and land
6-
Ans- Water Cycle
7-
Answer these questions:
Q. Mention some uses
of water.
Ans- Some of the uses of water are as follows:
Cooking
Cleaning utensils
Washing Clothes
Bathing
Irrigation of crops
Production in industries
Q. Name some sources of water.
Ans- Following are some sources of water:
(1) River
(2) Spring
(3) Pond
(4) Well
(5) Hand pump
(6) Lake
Ans- Some of the uses of water are as follows:
Cooking
Cleaning utensils
Washing Clothes
Bathing
Irrigation of crops
Production in industries
Q. Name some sources of water.
Ans- Following are some sources of water:
(1) River
(2) Spring
(3) Pond
(4) Well
(5) Hand pump
(6) Lake
Q. We need water not
only for our daily activities but also for producing many things. Explain.
Ans- We use rice, pulses, vegetables food items everyday. Fibre for making fabric comes from plants. Water is needed to grow them.
Water is used in industries for producing almost all the things that we use.
Q. Imagine a day in your life when water supply through taps is not available. What will you do to meet the needs of water?
Ans- If water supply through taps is not available to us for a day, we will have to fetch water ourselves from a far away place. We will use less amount of water that day.
Q. Why is the seawater not fit for drinking and other domestic, agricultural and industrial needs?
Ans- The seawater has many salts dissolved in it- the water is saline. So, it is not fit for drinking and other domestic, agricultural and industrial needs.
Q. How is salt obtained from seawater?
Ans- To obtain salt water from the sea is left in shallow pits to let the water evaporate. Salt is left behind in this process.
Q. How does it rain?
Ans- Droplets of water remain floating in the air and appear to us as clouds. It so happens that many droplets of water come together to form large sized drops of water. Some drops of water become so heavy that they begin to fall. These falling water drops are called rain.
Q. Mention factors that are leading to shortage of water.
Ans- Following are the factors responsible for shortage of water.
1- Most of the water is in ocean and can not be used directly.
2- The level of ground water is decreasing with over usage.
3- With rising poulation, number of people using water is also increasing.
4- More and more water is being used for producing food and by industries.
Q. What do you understand by rainwater harvesting? Discuss the techniques of rainwater harvesting.
Ans- The basic idea behind rainwater harvesting is to catch water where it falls. In rainwater harvesting, water is collected and stored for later use.
Ans- We use rice, pulses, vegetables food items everyday. Fibre for making fabric comes from plants. Water is needed to grow them.
Water is used in industries for producing almost all the things that we use.
Q. Imagine a day in your life when water supply through taps is not available. What will you do to meet the needs of water?
Ans- If water supply through taps is not available to us for a day, we will have to fetch water ourselves from a far away place. We will use less amount of water that day.
Q. Why is the seawater not fit for drinking and other domestic, agricultural and industrial needs?
Ans- The seawater has many salts dissolved in it- the water is saline. So, it is not fit for drinking and other domestic, agricultural and industrial needs.
Q. How is salt obtained from seawater?
Ans- To obtain salt water from the sea is left in shallow pits to let the water evaporate. Salt is left behind in this process.
Q. How does it rain?
Ans- Droplets of water remain floating in the air and appear to us as clouds. It so happens that many droplets of water come together to form large sized drops of water. Some drops of water become so heavy that they begin to fall. These falling water drops are called rain.
Q. Mention factors that are leading to shortage of water.
Ans- Following are the factors responsible for shortage of water.
1- Most of the water is in ocean and can not be used directly.
2- The level of ground water is decreasing with over usage.
3- With rising poulation, number of people using water is also increasing.
4- More and more water is being used for producing food and by industries.
Q. What do you understand by rainwater harvesting? Discuss the techniques of rainwater harvesting.
Ans- The basic idea behind rainwater harvesting is to catch water where it falls. In rainwater harvesting, water is collected and stored for later use.
Following are two
techniques of rainwater harvesting:
1- Rooftop rainwater harvesting for use- Rainwater is collected in a storage tank from the rooftop through pipes. This water needs to be filtered before use.
2- Rooftop harvesting for groundwater recharge- Another way is to let water seep into the soil instead of collecting it in storage tanks. This method is used to recharge / refill ground water.
3- Ground water recharge through roadside drains- Rainwater in roadside drains is allowed to go into the ground directly.
1- Rooftop rainwater harvesting for use- Rainwater is collected in a storage tank from the rooftop through pipes. This water needs to be filtered before use.
2- Rooftop harvesting for groundwater recharge- Another way is to let water seep into the soil instead of collecting it in storage tanks. This method is used to recharge / refill ground water.
3- Ground water recharge through roadside drains- Rainwater in roadside drains is allowed to go into the ground directly.
Exercises from Textbook
Fill
up the blanks in the following:
(a) The process of changing of water into
its vapour is called evaporation.
(b) The process of changing water vapour
into water is called condensation.
(c)
No
rainfall for a year or more may lead to draught in that region.
(d) Excessive rains may cause flood.
State
for each of the following whether it is due to evaporation or condensation.
(a) Water drop appears on the outer surface
of a glass containing cold water.Condenastion
(b) Steam rising from wet clothes while they
are ironed. Evaporation
(c)
Fog
appearing on a cold winter morning. Condensation
(d) Blackboard dries up after wiping it. Evaporation
(e) Steam rising from a hot griddle when
water is sprinkled on it. Evaporation
Which
of the following statements are true?
(a) Water vapour is present in air only
during the monsoon. False
(b) Water evaporates into air from oceans,
rivers, lakes but not from the soil. False
(c)
The
process of water changing into its vapour, is called evaporation. True
(d) The evaporation of water takes place
only in sunlight. False
(e) Water vapour condenses to form tiny
droplets of water in the upper layers of air where it is cooler. True
Suppose
you want to dry your school uniform quickly, would spreading it near an
aanghiti or heater help? If yes, how?
Yes, the
anghiti or heater will heat up the surrounding air. This warm air provides heat
for evaporation of water from school uniform.
Take
out a cooled bottle of water from refrigerator and keep it on a table. After
some time you notice a puddle of water around it. Why?
We notice a
puddle of water around the cooled bottle of water. The water vapours present in
the atmosphere get condensed near the surface of cooled water bottle and form a
puddle after sometime.
To
clean their spectacles, people often breathe out on glasses to make them wet.
Explain why the glasses become wet.
To clean the
spectacles, people often breathe out on glasses. The air that we breathe out
contains moisture. This moisture (water vapours) present in the exhaled air gets
condensed on the surface of glasses.
How
are clouds formed?
Water vapours continuously enter into the atmosphere through
the processes of evaporation and transpiration. At sufficient Heights,
the air becomes so cold that the water vapour present in it condenses to form
tiny drops of water called droplets. It is these tiny droplets that remain
floating in air and appear to us as clouds.
When does a drought occur?
Drought occurs if it doesn't rain in a region for a year or
more. The soil continues to lose water by evaporation and transpiration. Since
it is not being brought back by rain, the soil becomes dry. The level of water
in ponds and wells of the region goes down and some of them may even dry up.
The ground water may also become scarce. This may lead to drought.
Tables from Textbook
Table 14.1
Estimation of amount of water used by a family in a day
(You may use a
mug, a glass, a bucket or any other container to measure the amount of water
used)
Activity
|
Amount
of water used (in glasses)
|
Drinking
|
15
|
Brushing
|
2
|
Bathing
|
60
|
Washing utensils
|
240
|
Washing clothes
|
450
|
Toilets
|
150
|
Cleaning floor
|
150
|
Any other (Cooking)
|
10
|
Total water used in a
day by a family
|
1077 glasses
|
Suggested Projects and Activities
1-
List
three activities in which you can save water. For each activity describe how
would you do it.
2-
Collect
pictures relating to floods or drought from old magazines or news pares. Paste
them in your notebook and write about the problems that people would have
faced.
3-
Prepare
a poster on ways of saving water and display it on your school notice board.
4-
Write
a few slogans of your own on the topic ‘Save Water’.
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