How do I instantly increase or decrease air pressure?

Question

I am doing this experiment with a homemade barometer, and for this presentation, I need to show that this barometer works. So, how do I instantly increase or decrease air pressure? Any ideas?

Answer 1

It is hard to say without knowing how portable you want it or what kind of case you are working inside of.

Heating or cooling a closed container of air will do it but it is easier and more reliable to just have the dimensions of the airspace change quickly by using a sliding diaphram pump such as you see in a cloud chamber or you could use a flexible enclosure and squeeze it, another alternative that may work depending on your enclosure would be to use a pump such as a tire pump or aquarium pump.

You can also take the aparatus up or down a significant amount of elevation which is what was done for the original experiments that proved basic barometric principles.

Answer 2

You could place the barometer in a sealed transparent container like a fish tank, which has a rubber sheet sealed around the open side. When you push down on the rubber sheet, you will compress the air inside and increase the pressure; when you pull it up you will expand the air and reduce the pressure. Since the sides of the tank are clear glass, you should see the barometer responding appropriately.

Answer 3

Try using the wand from a vacuum cleaner. Use the wand with no attachments, and as you move it across the barometer you may get a drop in pressure.

Answer 4

Add or remove heat.