Saturday, January 14, 2012
Science Class 7th Answers of Chapter 8 – Winds, Storms And Cyclones
(a) Wind is ________ air.
(b) Winds are generated due to ________
heating on the earth.
(c) Near the earth’s surface __warm__
air rises up whereas _______ air comes down.
(d) Air moves from a region of __________
pressure to a region of ________ pressure.
Answer 1: (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
pressure to a region of low
pressure.
Question
2: Suggest two methods to find out wind direction
at a given place.
(i) While flying a kite, air exerts pressure on the kite due to which the kite flies. The direction in which the kite flies is the direction of blowing of wind.
(ii) While riding a bicycle, the direction in which it is difficult to ride is opposite to the direction of the blowing wind.
Therefore, while flying a kite or riding a bicycle, the wind direction at a given place can be determined.
Question
3: State two experiences that made you think that
air exerts pressure (other than those given in the text).
We have also experienced the movement of fringes (decorative border) of windows and doors of our houses when wind blows in a high speed. This also happens because air exerts pressure.
Question
4: You want to buy a house. Would you like to buy a
house having windows but no ventilators? Explain your answer.
Question
5: Explain why holes are made in hanging banners
and hoardings.
That is why holes are made in hanging banners and hoardings.
Question
6: How will you help your neighbours in case
cyclone approaches your village/town?
Answer 6: In case cyclone approaches,
the neighbours should be helped in the following ways.
(i) By helping in moving to cyclone
shelters and other safer places specially built for cyclones.
(ii) By asking them to take necessary steps to
shift animals, vehicles and household goods to safer places, which are stronger
and can handle cyclone effects.
(iii) By immediately calling the
emergency services such as police, fire brigade and medical centres when
required.
Question
7: What planning is required in advance to deal
with the situation created by a cyclone?
(i) Facilities for cyclone
prediction and forecasting which can give cyclone warning enough in advance.
(ii) Quick information and communication
linkages and systems so that information can be spread quickly.
(iii) Construction of cyclone
shelters and arrangement for moving people to safer places for safety during
cyclone.
Question
8: Which of the following places is unlikely to be
affected by a cyclone?
(i) Chennai (ii) Mangaluru
(Mangalore)(iii) Amritsar (iv) Puri
Answer 8: (iii) Amritsar as all other places are near to
coastal areas and thus the probability of cyclones in areas close to sea is
more.
Question
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.
In winter the winds flow from the land to the ocean as land remains cooler for a longer time compared to water in the sea/ocean. This is called land breeze.
(ii) Not Correct
In summer the winds flow from the ocean towards the land as land gets quickly hotter compared to water in sea/ocean. This is called sea breeze.
(iii) Not Correct
A cyclone is formed by a very low-pressure system with very high-speed winds revolving around it. The low-pressure region is called the eye of the cyclone.
(iv) Not Correct
The coastline of India is very vulnerable to cyclones as cyclones need supply of warm air that is available near coastline.
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