Water | Science 6th | Chapter 14 | Questions and Answers

JANDKNCERT | Science 6^th |

Water | Science 6th | Chapter 14 | Questions and Answers

 

Chapter 14: Water

Dear Students, in Chapter 13, you learnt about the Fun with Magnets, in which you learnt about the magnets, types of magnets, properties of magnets, and their uses. You also learnt about magnetic materials, such as iron, nickel and non-magnetic materials, such as rubber, plastic. Magnets help in finding the directions. Magnets always have two poles, that is, the North Pole and the South Pole.

In this chapter, you will learn about Water. The following points will help you to understand this chapter easily.

•       Water is essential for life.

•       Water vapour gets added to the air by evaporation and transpiration.

•       The water vapour in the air condenses to form tiny droplets of water, which appear as clouds. Many tiny water droplets come together and fall as rain, snow or hail.

•       Rain, hail and snow replenish water in rivers, lakes, ponds, wells and soil.

•       The circulation of water between the ocean and land is known as the water cycle.

•       Excessive rains may cause floods while lack of it for long periods, may cause droughts.

•       The amount of usable water on earth is limited so it needs to be used carefully.

 

Let us try to answer some questions taken from the NCERT Book of Science Class 6th. This Exercise is taken from the same book.

 

Exercises

Q1. 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 _________.

e. The ________ point of ice is 0^oC.

f. Floods damage soil by causing its_______.

 

Answer.

a. The process of changing 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 floods.

e. The melting point of ice is 0^oC.

f. Floods damage soil by causing its erosion.

 

Q2. 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.

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. Blackboard dries up after wiping it.

Ans. Evaporation

 

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

Ans. Evaporation

 

Q3. Which of the following statements are “true”?

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

b. Water evaporates into the 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. (True)

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

 

Q4. Suppose you want to dry your school uniform quickly. Would spread it near and anti or heater help? If yes, how?

 

Answer.

Yes, spreading school uniform near an angithi or heater would help us to dry it quickly because angithi or heater, heats the surrounding air that evaporates the water of uniform and thus helps to dry it quickly.

 

Q5. Take out a cooled bottle of water from the refrigerator and keep it on a table. After some time you notice a puddle of water around it. Why?

 

Answer.

When a cooled bottle of water is taken out from the refrigerator, the cold surface of the glass cools the air around it and the water vapour of air condenses on the surface of the glass that is why we see a puddle of water around it.

 

Q6. To clean their spectacles, people often breathe out on glasses to make them wet. Explain why the glasses become wet.

 

Answer.

While cleaning the spectacles we breathe out warm air on it. Since the surface of the glasses of spectacles is cold, so when our warm air comes in contact with a cold surface, it condenses and forms water droplets on the glass surface. These condensed droplets help us to clean our spectacles.

 

Q7. How are clouds formed?

 

Answer.

When the air heats up on the earth, it becomes lighter and is pushed up to the higher places in the atmosphere. At sufficient heights, the air becomes so cool that the water vapour present in it condenses to form tiny drops of water. It is these tiny droplets that remain floating in the air and appear to us like clouds.

 

Q8. When does a drought occur?

 

Answer.

If it does not rain for a year or more, the water from the soil will lose water by evaporation and transpiration. Everything will dry up and there will be no water anywhere. This will lead to drought.

 

Q9. Explain the formation of the water cycle?

 

Answer.

The circulation of water between the ocean and land is known as the water cycle. The water cycle takes place in three processes. The first process is evaporation. In this process, the water heats up due to the heat of the sun and moves up higher in the form of steam or water vapour. The second process is condensation. In this process, the water vapour cools down or condenses to form tiny water droplets. These droplets appear to us like clouds. The third process is precipitation. After the formation of droplets of water, many of these come together to form large-sized drops of water. When these drops of water become heavy, they begin to fall on the earth in the form of rain, hails or snow. Some of this rainwater gets absorbed by the ground, some flow down through rivers, streams, seas and ultimately joins the oceans again. Thus, water from the ocean and the surface of the earth goes into the air as vapour; returns as rain, hail or snow and finally goes back to the ocean. The circulation of water in this manner is known as the water cycle.

 

Q10. What do you understand by

a. Groundwater

 

Answer.

After the rainfall, some of the rainwater gets absorbed into the ground in the form of groundwater. We get this water from wells, lakes, springs, and hand pumps.

 

b. Running water

 

Answer.

The water that flows down the mountains in the form of streams and rivers after the melting of snow or ice is known as running water.

 

c. Rainwater harvesting

 

Answer.

The collection of rainwater to store it for later use is known as rainwater harvesting. In this method, the rainwater from the rooftops is collected and stored in tanks after purification and then used for many purposes.