DEMONSTRATION #3 - Flying Ping-Pong Ball

Supplies:

Hand held hair dryer, or vacuum cleaner with blower function and hose

Ping-Pong balls (1 or more)

Procedure:

Turn on the dryer or vacuum cleaner and hold it so the air blows straight up. Drop a Ping-Pong ball onto the center of the stream of air. A low power stream of air will work better than a more powerful stream. The ball will dance around suspended in the air. With practice, you can move it around the room without having it fall down. Try the same thing with a 1" by 6" strip of paper. Hold the paper just below the stream of air.

Explanation:

The stream of air going over the curved surface produces an area of lower pressure, pulling the object in the direction of the lower pressure. This is part of what is known as Bernoulli's Principle and is part of the explanation of how airplane wings get their lift. Since the ball is round, not wing shaped, the pressure is all around so the ball stands approximately still. With the paper, lift is actually created and demonstrated.