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 the region of __________ pressure to a region of __________ pressure.
(a) Wind is moving air.
The moving air is called wind.
(b) Winds are generated due to uneven heating on the earth.
Uneven heating on the earth is the main cause of wind movements.
(c) Near the earth's surface hot air rises up whereas cold air comes down.
The warm air is lighter than the cold air. Warm air rises up, whereas comparatively cooler air tends to sink towards the earth’s surface.
(d) Air moves from the region of high pressure to a region of low pressure
Air moves from the region where the air pressure is high to the region where the pressure is low. The greater the difference in pressure, the faster the air moves.
Suggest two methods to find out wind direction at a given place.
The two methods to find out wind direction at a given place:
(i) Take some sand and release from the height. The direction in which the sand starts flowing is the direction of wind.
(ii) Take a thin cloth and tie it with a stick. Keep the stick at high place. The direction in which cloth sways shows the direction of wind.
State two experiences that made you think that air exerts pressure (other than those given in the text).
Two experiences that depict the air exerts pressure are:
(i) It is difficult to ride a cycle against the direction of the wind. It shows that the air exerts pressure while riding a cycle.
(ii) It is difficult to row a sailboat against the direction of the wind but it is much easier in the direction of the wind. It also shows that the air exerts pressure on the sail of the boat.
You want to buy a house. Would you like to buy a house having windows but no ventilators? Explain your answers.
No, I would not like to buy a house having windows but no ventilators. Warm air is lighter which rises up and exit from the ventilators. Cool air is heavier which moves in through window. This will help in making the rooms comfortable for living.
Explain why holes are made in hanging banners and hoardings.
Holes are made in the hanging banners and hoardings to allow air to pass through them without damaging them. This helps in reducing the impact of air pressure on the hoardings and thus they are not blown away.
How will you help your neighbours in case cyclone approaches your village/town?
I will help my neighbours in case cyclone approaches my village/ town by the following ways:
(i) I will inform them about the weather forecast, alters and warnings.
(ii) I will help in shifting their household articles, domestic animals to safe place.
(iii) I will also arrange for drinking water and food.
(iv) I will provide first aid to injured people.
(v) I will provide phone numbers of all emergency services like police, fire brigade and medical centers.
(vi) I will give them safety advice like avoid driving on roads through standing water, not to touch wet switches, etc.
What planning is required in advance to deal with the situation created by the cyclone?
A good planning in advance will minimize the damages to be caused by a cyclone. Following planning is required to deal with the situation created by a cyclone:
(i) The cyclone warnings issued by the meteorological department through TV, radio, or newspapers should not be ignored.
(ii) The necessary arrangements to shift the essential household goods, domestic animals and vehicles, etc. to safer places should be made.
(iii) The phone numbers of all emergency services like police, fire brigade, and medical centers should be kept ready.
Which one of the following place is unlikely to be affected by a cyclone?
(a) Chennai
(b) Mangaluru (Mangalore)
(c) Amritsar
(d) Puri
Correct
Amritsar is least likely to be affected by a cyclone because it is far away from the coastal areas.
Which of the following 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 speed pressure system with very high speed winds revolving around it.
(iv) The coastline of India is not vulnerable to cyclones.
Correct
In winter, the land surface cools up faster as it loses its heat than that of water bodies in the ocean. The air over the sea surface rises up and cool air from the land surface move towards the sea. This is land breeze.