Air Pressure - How hot air expands

An Air Pressure Experiment

If you want an experiment to show how air expands as it gets warmer, you’ll enjoy this simple experiment!

You will need:

·         An empty 2l bottle

·         A balloon

·         A freezer

·         A sink of warm water

What you’ll need to do:

1.       Blow up a balloon slightly  

2.       Carefully put it over the opening of the empty bottle.

3.       Put the bottle with the balloon attached in the freezer for at least 10 minutes

4.       While you’re waiting get a fairly warm sink full of water ready

5.       After the 10 minutes is up get the bottle with the balloon out of the freezer.  What do you notice about the balloon? There is no air in it anymore!

6.       Submerge most of the bottle into the water.  What to you notice now? The balloon is full of air again!  This is because the air inside of the balloon is warming up and expanding.  The same way as warm air in the atmosphere gets warmer, expands getting lighter, rises and creates a low pressure area.