Water
I.Fill in the blanks in the following:
a)
The process of changing of water into the vapour is called Evaporation or
vaporisation
b) The
process of changing water vapour into water is called Condensation
c) No
rainfall for a year or more may lead to Droughts in that region.
d) Excessive rains may cause Floods
II. State each of the following whether it is due to evaporation or condensation:
a)
Water drops appear on the outer surface of a glass containing cold water
Ans: Condensation
b)
Steam rising from wet clothes while they are ironed.
Ans: Evaporation
c) Fog
appearing on a cold winter morning
Ans: Condensation
d)
Black board dries up after wiping it
Ans: Evaporation
e)
Steam rising from a hot girdle when water is sprinkled on it
Ans: Evaporation
III. Which of the following statement are
true?
a) Water vapour is present in air only during the monsoon. False
b)
Water evaporates into air from oceans, rivers and lakes but not from the soil. False
c) The
process of water changing into its vapor 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 layer of air where it is cooler. True
IV. Answer the following:
1.
Suppose you want to dry your school uniform quickly, would spreading it near an
anghiti or heater help? If yes, how?
Ans: Yes, spreading it near heater will surely help as heater and anghiti
are source of heat which vaporize the water of the wet clothes and thus help in
drying
2.
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?
Ans: The puddle of water seen around the cooled bottle of water is due to
the condensation effect as the water vapour present in the air around the
bottle gets condensed after colliding with bottle.
3. To
clean their Spectacles People, of-ten breathe out on glasses to make them wet.
Explain why the glasses become wet
Ans: Water vapour also gets released during exhalation process along with
carbon dioxide The water vapour gets attached with the glasses of the
spectacles and then condenses in the presence of air surrounding it and thus
making it wet.
4. How
are clouds formed?
Ans: When the air moves up, it gets cooler and cooler and after reaching
sufficient height the air becomes so cool that the water vapour present in it
condenses to form tiny drops of water called droplets which remain floating in
air and thus clouds are formed.
5.
When does a drought occur?
Ans: Drought occurs when an area does not receive rainfall for a period of
year or more, also the soil continues to lose water by evaporation and
transpiration and becomes dry and the ground water may also become scarce which
may lead to drought.
0 Comments