Demonstration
Air weighs in
By: Brad Niimi

Supplies
1. A yard or meter stick.
2. 2-3 feet of fishing line.
3. At least four latex balloons.
4. Two thumbtacks.Principles discussed
5. Gravity
6. Mass and weight.

Method
1. Balance meter stick, drill hole through meter stick at center of mass or
tie fishing line around center and secure with tape.
2. Attach uninflated balloons to ends of balancing yardstick. Show that
they balance.
3. Remove one balloon and inflate it, then reattach to yardstick. The
inflated balloon will weigh more than the uninflated balloon.
4. If Students doubt results, blow up both balloons (be sure to inflate to
about the same amount).
The yardstick should balance again.