Q.1 Fill the missing word in the blank spaces in the following statements:
(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.
NCERT Solutions for Class 7 Science Chapter 8 Winds Storms And Cyclones
Answer :
(a) Wind is moving air.
(b) Winds are generated due to uneven heating on the earth.
(c) Near the earth’s surface, warm air rises up whereas cold air comes down.
(d) Air moves from a region of high air pressurere to a region of low air pressure.
NCERT Solutions for Class 7 Science Chapter 8 Winds Storms And Cyclones
Answer :
Methods to find out the wind direction at a given place are as follows
(i) By seeing the direction of dry leaves released in the air.
(ii) Take a piece of a thread in your hand. Allow it to fall from your hand. It will flow in the direction in which the wind is blowing.
(iii) While flying a kite, the direction in which the kite flies shall be the wind direction.
(iv) Take some fine and light sand in your hand and slowly slip it off. The movement of dust particles in a particular direction will give the direction of the wind.
(v) An instrument called an anemometer can be used to find the direction and speed of the wind.
Q.3 State two experiences that made you think that air exerts pressure (other than those given in the text).
NCERT Solutions for Class 7 Science Chapter 8 Winds Storms And Cyclones
Answer :
Experiences that made you think that air exerts pressure:
(i) Balloons and balls can be used only when they are inflated with air. When the balloon is overfilled with air it bursts due to excessive air pressure.
(ii) Blowing air can move curtains on doors and windows.
(iii) Cycling against the direction of the wind, it is difficult to ride. It shows that the air exerts pressure.
(iv) While rowing a sailboat in the direction of the wind, it is always easier to row and while rowing a sailboat against the direction of the wind, it is very difficult to row. It also shows that the air exerts pressure
Q.4 You want to buy a house. Would you like to buy a house having windows but no ventilators? Explain your answer.
NCERT Solutions for Class 7 Science Chapter 8 Winds Storms And Cyclones
Answer :
No, a house that has no ventilators is not a safe or healthy house to live in.
(i) The air circulation is not there in such a house. So, it has no fresh air.
(ii) Warm air is lighter than cold air hence warm air passes out of your home through ventilators.
Accordingly, without ventilators, warm air will not pass out, and the house will remain warm.
Thus, without ventilators, the house will become uncomfortable to live in.
NCERT Solutions for Class 7 Science Chapter 8 Winds Storms And Cyclones
Answer :
Holes are made in hanging banners and hoardings so that air can pass through them easily and reduce the air pressure.
If banners and hoardings do not have holes, the pressure exerted by wind may tear them off, loosen them or make them fall.
NCERT Solutions for Class 7 Science Chapter 8 Winds Storms And Cyclones
Answer :
In case cyclone approaches, the neighbors should be helped in the following ways:
(i) By moving them to cyclone shelters and other safer places.
(ii) By keeping storage of water and food.
(iii) By calling emergency services such as fire stations, police, and medical centers.
(iv) By helping in shifting animals, vehicles, and household goods to safer places.
(v) By giving safety advices like avoid driving on roads through
standing water, not touching wet switches, etc.
(vi) By informing them about the weather forecast and warnings.
(vii) By arranging drinking water and food.
(viii) By providing first aid to injured people.
NCERT Solutions for Class 7 Science Chapter 8 Winds Storms And Cyclones
Answer :
The following planning is required to deal with the situation created by a cyclone:
1). Carefully listening to the warnings transmitted on T.V and radio.
2). Moving to safer places.
3). Keeping an emergency kit ready.
4). Storing food in waterproof bags and storing water.
5). No venturing into the sea.
6). Avoid driving on roads through standing water, as floods may have damaged the roads.
7). Keeping phone numbers of all emergency services like police, fire brigade, and medical centers.
8). Setting up first aid facilities.
9). Not touching wet switches and fallen power lines.
Q.8 Which one of the following places is unlikely to be affected by cyclone?
(i) Chennai
(ii) Mangalore
(iii) Amritsar
(iv) Puri
NCERT Solutions for Class 7 Science Chapter 8 Winds Storms And Cyclones
Answer :
(iii) Amritsar
Among the mentioned places, only Amritsar is located far away from the coastal area, all the other places namely Chennai, Mangalore, and Puri are located near the sea. So Amritsar is unlikely to be affected by a cyclone.
Q.9 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.
NCERT Solutions for Class 7 Science Chapter 8 Winds Storms And Cyclones
Answer :
(i) In winter the winds flow from the land to the ocean.