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"Under Pressure" Experiments

Air Pressure 7 - Make a Barometer

Experiment: To make a simple barometer.

Materials:

You will need:

Empty, clear jam jar
A balloon
A straw
A few elastic bands
A piece of card

Method:

What you have to do: 

1) Blow up a balloon to stretch it - then let out the air.

2) Cut the balloon in half.

3) Wrap the bottom half of the balloon around the top of the jam jar. Make sure that it is stretched tightly across the top.

4) Wrap elastic bands tightly round the edges of the balloon to fix it securely to the jar.

5) Cup the bendy end of your straw and sellotape the long bit that you have left to the centre of the balloon.

6) Fold the card in half so that it stands upright and mark the card where the straw is pointing.

7) Draw a scale on the card - high at the top and low at the bottom of the card.

Result: The straw will point to high when it's sunny and low when it is raining or there is bad weather.

Conclusion: When there is higher pressure around the jar, it will push down on the balloon and that will make the straw point towards high when you stand the card up beside it. When the pressure around the jar is lower, the higher pressure in the jar will make the balloon inflate and push the straw to point to low.

 

Sixth Class Experiments