Page 108 - Genius Kidz Prudence Learning Sc-8
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LIGHTNING · During the development of a thunderstorm
Lightning is one of the most beautiful displays the currents move upward while the water
in nature but it is also one of the most deadly droplets move downward.
natural phenomena known to man. With high · This vigorous movement and continuous
temperatures hotter than the surface of the rubbing causes development of separate
sun and shockwaves beaming out in all charges.
directions, lightning if it strikes the earth is a · Somehow positive charge gets accumu-
disastrous natural calamity. lated near the top edge of the cloud and the
negative charge at the lower edge. At the
same time there is an accumulation of
positive charge near the ground as well.
· Air being a poor conductor of electricity,
cannot resist the flow of charges for too
long.
· Negative and positive charges meet
producing streaks of bright light and sound.
Lightning This process is called an electric discharge.
To understand better what lightning is recall · The electric discharge can occur between
that you must have seen sparks on an electric two or more clouds or within a cloud or
pole when wires becomes loose. Or you must between clouds and the earth.
have seen sparks when a plug is loose in its Safety from lightning
socket. So, lightning is also an electric spark but · Hearing thunder is an alarm to rush to a
on a huge scale. safer place.
Cause of Lightning · A house or a building or a car with all its
Charges are produced on objects by rubbing. In doors and windows shut is safe.
the process of rubbing an object acquires · Carrying a black umbrella or an umbrella
either a negative charge or a positive charge. with a metal rod is dangerous during
The electric charges generated by rubbing are thunderstorms, accompanied by lightning.
static i.e they do not move. When charges
· While in an open space stay away from
move they constitute an electric current. A
poles or other metal objects(being good
device called electroscope is used to detect
conductors of electricity).
whether an object is carrying charge or not.
· During lightning the safest position to sit is
We also very well know that the opposite
to be on your toes with your head bent on
charges attract each other while the like
your knees. This position is known as squat
charges repel each other.
position and it makes you a smaller target
The very same phenomenon i.e getting
to be struck.
charged on rubbing and then attraction
Explain the working of a gold leaf
between opposite charges towards each other
electroscope along with a diagram.
causes the lightning. Let us see how-
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