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We all know that whatever
is thrown up always comes down. This is due to a force called
gravity - which comes
from the centre of the earth and attracts
everything (physical things, living beings) to the surface of
the earth. This is why we are able to walk on earth otherwise we would be
flying around. Little children have great fun experimenting with this idea -
especially when it comes to throwing things on the floor and expecting other
people to pick them up!
One of the
objects that obey this law of gravity is the parachute. In real life, parachutes are very valuable
since they used in emergency situations when people need to exit off a plane
that is not functioning correctly. The parachute allows a person to land on
the ground safely, but requires lot of training. The time taken to reach the
ground depends on the weight of the
person, the wind speed, parachute size etc. You too can
create a parachute at home and experiment with it.
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Materials Needed : A plastic carrier bag
Long piece of thread or string
Scissors
Ruler
Cellotape
A small toy or object
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Procedure
:
- Choose a strong
carrier bag and cut out a large
circle from it.
- Divide the circle
into 6 equal parts, as shown in the diagram and make 6 small holes.
- Cut the thread or
string into six equal pieces (make them about one and a half times the size of the circle
diameter. For e.g. if the diameter is 5, then the length
of the string will be 5 x 1.5 = 7.5) Using cellotape,
attach each of the strings to the holes.
- Lastly, tie the open ends of the strings to your toy
(MAKE SURE your toy is not heavy).
- Now the parachute
is ready to be launched. Throw
it up in the air or climb up to a high level and release it.
You will see the plastic sheet fill up and the parachute will gently
float to the ground.
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HOW DOES IT WORK? Why doesn't the toy
fall to the ground immediately as normal? Since the toy is attached to the
plastic sheet, when it begins to fall air fills up in the canopy and resists or prevents free fall.
This force is acting upwards
and we still have the force of gravity acting downwards. If the forces were
equal in strength, the parachute would not move; it would be stuck in the
air, but since gravity is stronger,
the parachute is attracted downwards and so it floats down slowly.
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Working of a parachute
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