CLASS 7 SCIENCE CHAPTER 8 WINDS, STORMS AND CYCLONES NCERT QUESTION ANSWER SOLVED

NCERT Exercise

(a) Wind is________air.
(b) Winds are generated due to_________heating on the earth.
(c) Near the earth’s surface __________air rises up whereas ___________ air comes down.
(d) Air moves from a region of _________ pressure to a region of_________ pressure.

Answer:

(a) Wind is moving air.
(b) Winds are generated due to uneven heating on the earth.
(c) Near the earth’s surface hot air rises up whereas cool air comes down.
(d) Air moves from a region of higher pressure to a region of lower pressure.

2. Suggest two methods to find out wind direction at a given place.

Answer:

Two methods to find out wind direction at a given place are,

(i) a piece of paper in the air. The piece will fly in the direction of the wind.
(ii) Take some lighter sand in your hand and slowly slip it off.

3. Take experiences that made you think that air exerts pressure (other than those given in the text).

Answer:

Examples of air exerts pressure are:

4. You want to buy a house. Would you like to buy a house having windows but no ventilators? Explain your answer.

Answer:

No, a house having windows but not ventilators shouldn’t be bought.
Without ventilators the house is not healthy and safe because the air circulation is not proper to live.
The warm air is lighter than the cold air and it flows easily.
So, the increased warm(heat) inside the home goes outside by ventilators and fresh air come inside through windows.
Therefore, if there are no ventilators, then warm air can’t go outside.

5. Explain why holes are made in hanging banners and hoardings.

Answer:

Blowing air pass through the holes.
Air blowing in high speed can break many things.
If holes are made in hanging banners and hoardings, then air can pass through these holes which helps to reduce the air pressure.
Therefore, holes are made in hanging banners and hoardings.

6. How will you help your neighbours in case cyclone approaches your village/town?

Answer:

If cyclone approaches our village/town, then we should help our neighbours in the following manner.
i.) By helping them in moving to cyclone houses.
ii.) By asking them to shift essential household goods, domestic animals and necessary things to safer places.
iii.) When required by calling emergency services like police, medical sectors, fire brigade and other emergency services.

7. What planning is required in advance to deal with the situation created by a cyclone?

Answer: To deal with the situation created by cyclone the following planning is required:

Carefully listening all the warnings issued by meteorological department through TV, radio, or newspaper.
Making necessary arrangements and shifting to safer cyclone shelters or other places.
Keeping essential household goods ready.
Keeping the number of all emergency services.
Not moving into the sea.

(iv) Which one of the following place is unlikely to be affected by a cyclone.

Answer:
(iii) Amritsar

(v) Which of the statements given below is correct?

(i) In winter the winds flow from the land to the ocean.
(ii) In summer the winds flow from the land towards the ocean.
(iii) A cyclone is formed by a very high-pressure system with very high-speed winds revolving around it.
(iv) The coastline of India is not vulnerable to cyclones.

Answer:
(i) In winter the winds flow from the land to the ocean.