Chapter 14 Water

NCERT Solutions for Chapter 14 Water from Class 6

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 1

(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 2

(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 3

(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 4 Yes, spreading of clothes near an anghiti or heater help to dry school uniform quickly.This is because the rate of evaporation increases with increase in temperature.

Question 5. Take out a cooled bottle of water from refrigerator and keep it on a table. After some time you notice a droplets of water around it. Why?

Answer 5 Since the water bottle is at a very low temperature the surface exposed is also very cold. As the cool surface is exposed, condensation of water vapour present in the air occurs. Now the condensed water molecules spread around the bottle. So a puddle of water is noticed after some time.

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

Answer 6 The air we blow out contains water vapour. The water vapour condenses on the spectacles forming moisture and the glass is coated with a layer of minute water droplets.

Question 7. How are clouds formed?’

Answer 7 Water from water bodies evaporate due to heat by Sun. As these vapours go higher from the surface of the earth, 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 appear to us as clouds.

Question 8. When does a drought occur?

Answer 8 When there is no rain for many years over a long period of time then there will arise a scarcity of water in that locality or region. This leads to drought.Water lost by soil due to evaporation is returned to it by rain.