This is an easy project and would make a great science experiment. Using a vacuum inside a plastic bottle with water in it, you can observe the changing air pressure with this simple barometer. Please note, this type of barometer only allows you to see if the air pressure is high or low.
Step 1: Supplies
Items needed to make this barometer are:
1. A plastic soda or water bottle with lid, size not important!
2. Air Tubing, such as from an aquarium or oxygen use about 1 3/4 the length of the bottle.
3. A nail or other sharp instrument.
4. A rubber band
5. Low-Heat glue gun
6. Food Coloring (gel or liquid)