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.
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.
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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