FLOATING PIN PONG
Unleash the magician within you and use your mysterious powers to levitate a Ping-Pong ball! (Okay, so it's actually not that mysterious; in fact, you'll find the explanation right out of thin air!)
Make sure you have an adult present for performing this magical feat
since you will be using a hair dryer.
What you'll need:
a Ping-Pong ball or two
a hair dryer
What to do:
Set the hair dryer to cool, then turn on the hair dryer and hold it so that the stream of air is pointing straight up at the ceiling.
Place a Ping-Pong ball in the stream of air.
The Ping-Pong ball doesn't blow away; instead, it floats securely in midair! It stays that way even if you move the hairdryer to an almost horizontal position.
For an even freakier effect, try floating other lightweight objects in the airstream at the same time! With the hair dryer on, place a balloon over your levitating Ping-Pong ball, then add a beach ball or larger balloon weighted with paper clips on top of that!
Why this happens:
You've just witnessed a really wacky demonstration of the Bernoulli effect, and it's the same principle that allows heavier-than-air objects like airplanes to fly. Bernoulli, an 18th century Swiss mathematician, discovered a rather strange characteristic of moving air. He found that moving air exerts less pressure in a direction at right angles to its motion than still air does. Since the airstream from the hair dryer moves faster around the side ofthe ball (and thus exerts less pressure) than the still air on top of the ball, the heavier air pressure on top of the ball holds it firmly in midair.
Airplanes can fly because of this principle. Air rushing over the tops of airplane wings exerts less pressure than air from under the wings. So the relatively greater air pressure beneath the wings supplies the upward force, or lift, that enables airplanes to fly.