Class 6 Science NCERT Solutions for Chapter – 14 Water

Water

Question 1.
Fill in the blanks in the following :

(a) The process of changing of water into its vapour is called ______.
Answer:
Evaporation

(b) The process of changing water vapour into water is called ______.
Answer:
Condensation

(c) No rainfall for a year or more may lead to ______ in that region.
Answer:
Drought

(d) Excessive rains may cause ______.
Answer:
Floods

Question 2.
State for 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.
Answer:
Condensation

(b) Steam rising from wet clothes while they are ironed.
Answer:
Evaporation

(c) Fog appearing on a cold winter morning.
Answer:
Condensation

(d) Blackboard dries up after wiping it.
Answer:
Evaporation

(e) Steam rising from a hot girdle when water is sprinkled on it.
Answer:
Evaporation

Question 3.
Which of the following statements are “True” ?

(a) Water vapour is present in air only during the monsoon.
Answer:
False

(b) Water evaporates into air from oceans, rivers and lakes but not from the soil.
Answer:
False

(c) The process of water changing into its vapour, is called evaporation.
Answer:
True

(d) The evaporation of water takes place only in sunlight.
Answer:
False

(e) Water vapour condenses to form tiny droplets of water in the upper layers of air where it is cooled.
Answer:
True.

Question 4.
Suppose you want to dry your school uniform quickly.Would spreading it near an angithi or heater help? If yes,how ?

Answer:
Yes, it will help because rate of evaporation is increased when air becomes hot.

Question 5.
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 ?

Answer:
Air around the cooled bottle of water gets cooled and water vapour present in it condenses into water which collects as a puddle of water around the bottle.

Question 6.
To clean their spectacles, people often breathe out on glasses to make them wet. Explain why the glasses becomes wet.

Answer:
Breathed out air is hot and therefore when it comes in contact with colder glasses than water vapour present in it condenses to form water. This makes the glasses wet.

Question 7.
How are clouds formed ?

Answer:
When the air containing water vapour moves up, it gets cooler and cooler. At sufficient heights, the air becomes so cool 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 form clouds.

Question 8.
When does a drought occur ?
Answer:

Drought occurs when its does not rain for a long period.

InText Questions and Answers

Activity 1

Take two similar plates. Place one of the plates in sunlight and keep the other under shade. Now, pour equal amount of water in each of the plates (Fig. 14.1). You can use a cap of a bottle to measure water. Make sure that water does not spill over. Observe the two plates after every 15 minutes. Does the water seem to disappear? From which plate does it disappear first? what is the source of heat for this evaporation?
NCERT Solutions for Class 6 Science img 48
Answer:
Yes, water seems to disappear. It disappears first from plate kept in sunlight. Source of heat for this evaporation is sunlight.

Activity 2

Take a glass half filled with water. Wipe the glass from the outside with a clean piece of cloth. Add some ice into the water. Wait for one or two minutes. Observe the changes that take place on the outer surface of the glass (Fig. 14.2) and mention what happens.
NCERT Solutions for Class 6 Science img 49
Answer:
Drops of water appear on outer surface of the glass containing water with ice.

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