a does not care about storm rain and cold
Answers
Explanation:
SCIENCE
Winds, Storms 8 and Cyclones
O
rissa was hit by a cyclone with
wind speed of 200 km/h on
18 October 1999. The cyclone
smashed 45,000 houses making
7,00,000 people homeless. On
29 October the same year, a second
cyclone with wind speed of 260 km/h
hit Orissa again. It was accompanied by
water waves about 9 m high. Thousands
of people lost their lives. Property worth
crores of rupees was destroyed. The
cyclone affected agriculture, transport,
communication, and electricity supply.
But, what are cyclones? How are
they formed? Why are they so
destructive? In this chapter we shall
seek answers to some of these questions.
We begin with some activities
involving air. These activities will clarify
some basic features concerning a
cyclone. Before we begin, remember that
the moving air is called the wind.
8.1 AIR EXERTS PRESSURE
Activity 8.1
Fig. 8.1 Image taken by a satellite of a cyclone
approaching the coast of Orissa
Courtesy: India Meteorological Department,
New Delhi
Whenever an activity involves heating,
be very careful. It is advised that such
activities are per formed in the
presence of an elderly person from
your family. Or, carry out these
activities in the presence of your
teacher.
You need to boil water in the following
activity.
Take a tin can with a lid. Fill it
approximately half with water. Heat the
can on a candle flame till the water boils.
Let the water boil for a few minutes. Blow
out the candle. Immediately put the lid
tightly on the can. Be careful in handling
the hot can. Put the can carefully in a
shallow metallic vessel or a washbasin.
Pour fresh water over the can.
What happens to the shape of the can?