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Wonderful Weather - Experiment 4

1. Cloud in a bottle | 2. Tornado in a Bottle | 3 Air Pressure in a Jar | 4. Air Pressure on a glass| 5. Make a barometer  | 6. Make a Thermometer

Experiment: To demonstrate that air pressure is all around us.

Materials:

You will need:

Wine Glass
Water
Piece of Card
handkerchief (optional)

 

Method:

What you have to do: 

1) Fill your wine glass about half full.

2) Get your piece of card (which should fit around your wine glass).

3) Place it firmly on top of your wine glass.

4) With one hand on top of the card and another on the bottom of the glass, turn the glass upside down.

Result: Take your hand away from the card and it should stay in place. 

Conclusion: The reason why the card (and water) stayed in place is all to do with air pressure.
This pressure is pushing the card up which is keeping the water in also.

Try this: With this experiment, instead of using a piece of card, you can use a handkerchief. The only difference is that you place the handkerchief across the top of the glass (NOT tightly) and then fill to about half way with water. Then, pull the handkerchief tight and holding the glass (and handkerchief) tightly by the stem, turn the glass upside down. Water should remain in the glass.

With the glass upside down, slowly and carefully start to pull the wet handkerchief down the stem. You should find that the pressure of the air is pushing up and keeping it in place. See how far you can pull the handkerchief before it comes away.