NCERT Solutions Class 6 Science Chapter 14 Water

NCERT Solutions for Class 6 Science for chapter 14 Water

Question.1

Fill up the blanks in the following:

(a) The process of changing of water into its vapour is called _____.

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

(c) No rainfall for a year or more may lead to _____ in that region.

(d) Excessive rains may cause ______.

Answer.

(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 drought in that region.

(d) Excessive rains may cause flood.

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.

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

(c) Fog appearing on a cold winter morning.

(d) Blackboard dries up after wiping it.

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

Answer.

(a) Water drops appear on the outer surface of a glass containing cold water. (Condensation)

(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 girdle when water is sprinkled on it. (Evaporation)

Question.3

Which of the following statements are “true”?

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

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

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

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

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

Answer.

(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 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)

Question.4

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

Answer.

Yes, spreading of school uniform near an anghiti or heater would help to dry it quickly. Heat generated from anghiti or heater will warm up the surroundings. Water evaporates at faster rate in warm surroundings. Therefore, school uniform will dry up quickly by spreading it near an anghiti.

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.

Puddle of water is observed due to condensation of water vapours present in air around the surface of bottle.

The water vapours present around the surface of the bottle touch the ice-cold surface of the bottle and get converted to water droplets.

Question.6

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

Answer.

When we breathe out, water vapours along with carbon dioxide are released. If we breathe out on glasses, the released water vapours collide with surface of the glass and condense, thereby making it wet.

Question.7

How are clouds formed?

Answer.

Water from water bodies and plants is transferred to air through evaporation and transpiration. When the air (laden with water vapours) 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. These tiny droplets remain floating in air and appear to us as clouds.

Question.8

When does a drought occur?

Drought occurs when there is insufficient or no rain in a region for a long time. 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 even dry up. The level of ground water also goes down. These conditions lead to drought.