Wednesday, December 02, 2009

[Science Form 2] Experiment - Air Pressure

This is very interesting experiment. All you need is a hard-boiled egg, a bottle, and three matchsticks.

Here's what you do:
  1. Make sure the mouth of the bottle is just small enough to keep the egg from falling inside.
  2. Set the bottle on the table, and peel the egg.
  3. Light the three matchsticks and drop them into the bottle.
  4. Quickly place the egg over the mouth of the bottle.

This is what you would observe... the egg is sucked into the bottle.

1. Discuss with your partner how you would explain this phenomena and write it out.
Explanation: The lit matchsticks heat the air inside the bottle. When air is heated, it expands. As the heated air expands, some of it escapes out of the bottle. When the matches go out, the air inside the bottle cools and contracts, thus creating a lower air pressure inside the bottle than outside. The greater pressure outside the bottle forces the egg into the bottle.

2. Now, what would you do to get the egg out of the bottle?
Turn the bottle upside down and blow into it.

3. Explain your method.
The increased air pressure in the bottle will cause the egg to pop back out.

1 comment:

  1. why was the air could escaped? the bottle was supposed to be closed tightly, wasn't it??


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