Lesson: Wind, Storm and Cyclone
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.
(a) Moving
(b) Unequal
(c) Warm, cool
(d) High, low
Suggest two methods to find out wind direction at a given place.
Wind direction at a given place can be found out by:
(a) By using a wind vane: A wind vane is an instrument used for determining the direction of the wind. It spins and points in the direction from which the wind is coming.
(b) By flying kites: A flying kite points in the direction of the blowing wind.
State two experiences that made you think that air exerts pressure (other than those given in the text).
(a) A simple activity was carried out where one end of a small, narrow glass tube was dipped in water and then the other end was closed with a fingertip, and the tube was taken out. There was a column of water that had entered the tube which did not flow out until the finger was removed. This showed that the pressure of the column of water was balanced by the air pressure from below the tube opening, and that is why the water did not flow out.
(b) When an empty, crumpled paper bag was gathered around one’s mouth and was blown, it inflated and tightened due to air pressure. The air blown in exerted pressure on the paper walls to inflate the crumpled bag.
You want to buy a house. Would you like to buy a house having windows but no ventilators? Explain your answer.
Windows have their own function. But the presence of ventilators too is considered to be essential for a house. The purpose is to let out the warm air building up inside the rooms. Warm air, being lighter than cold air, goes up and goes out easily through ventilators, and invites cooler air from outside through the windows, thereby leaving the rooms cool.
Explain why holes are made in hanging banners and hoardings.
Holes are made in hanging banners and hoardings in order to reduce air pressure exerted by strong winds on the hoardings. By letting the wind pass through these holes, the impact of air pressure, generated by the strong wind, is reduced.
How will you help your neighbours in case cyclone approaches your village/town?
In case a cyclone approaches my village/town I shall help my neighbours in the following ways:
(a) By rapidly communicating the warning news of an approaching cyclone.
(b) By helping in constructing cyclone shelters.
(c) By making administrative arrangements for moving people fast to safer places.
(d) By making necessary arrangements to shift the essential household goods, domestic animals and vehicles, etc. to safer places.
(e) By keeping the phone numbers of all emergency services like police, fire brigade, and medical centres ready.
What planning is required in advance to deal with the situation created by a cyclone?
In order to deal with the situation created by a cyclone, the following planning is required in advance:
(a) Setting up of a system of quick communication of a cyclone forecast and warning service.
(b) Construction of cyclone shelters in the cyclone prone areas.
(c) Administrative arrangements for moving people fast to safer places.
Which one of the following place is unlikely to be affected by a cyclone?
(i) Chennai
(ii) Mangaluru (Mangalore)
(iii) Amritsar
(iv) Puri
(iii)
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.
(i)