KnowZone Rules!
What you will need for this experiment:

Empty Clean Plastic 1 Gallon Milk Jug
Napkins or Paper Towels
Masking Tape

What to do:

1. Cut the napkin into 5 strips that are about 2-inches wide.
2. Find a suitable place (indoors or outdoors) where there is little or no air movement.
3. Tape the top of each napkin to the edge of an object (bookshelf, table, fence, etc.). Make sure each strip is about 2 inches apart.
4. Stand at least 3 feet away from the napkin strips.
5. Hold the bottle in one hand and aim its mouth at the napkin strips.
6. Quickly pat the bottom of the bottle with your other hand to hit one or several napkin strip “targets” with a blast of air. It will take a little practice to hit each one individually.

Try making the hole smaller. How does it affect the blast of air? Try blasting your friends from a distance. How far can your blast go?
Air Velocity! Air is made of matter (mostly nitrogen and oxygen molecules). Even though air is invisible it takes up space. When you hit the bottom of the milk jug, you are reducing the size (or volume) of the jug and this increases the pressure within the jug. The increased pressure pushes some of the air out of the jug and you feel a blast of air. Its like squeezing a plastic mustard container - the mustard squirts out.

Last Updated on August 6, 2002
Questions?? Contact ewong@arb.ca.gov
A department of the California Environmental Protection Agency