Introduction: Bernoulli's Slalom

Using some household materials and some basic physics, you can have a fun game that is playable for hours.

Note: Ball may not glow as shown in the picture below.

Step 1: Gather Materials

For this project, all you need is string, clothes hangers, a hair dryer, and a ping-pong ball. You may also need an extension cord or tape.

Step 2: Build the Course

Tie a length of string to the clothes hanger and then hang it from the ceiling. As long as the clothes hanger is dangling freely in the air, it is okay. Repeat this with the rest of the coat hangers until you have something looking kind of like a mix between croquet and slalom gates.

Step 3: Levitate a Ball

Plug in the hair dryer and turn it on its highest speed. Hold it so that the air blows straight up. Then hold the ping-pong ball towards the top of the stream of air and let it go. It should be suspended in air becuase of Bernoulli's Principle. Bernoulli's Principle states that as the speed of a fluid (in this case air) increases, the pressure decreases. The momentum of the air coming out of the hair dryer provides the lift for the ball. The tendency of the ball is to be pushed out of the stream of air, but because the air stream is moving faster than the air around it, it creates low pressure, and sucks the ball back into the air stream.

Practice with keeping the ball up and moving the hair dryer around. You may want to plug the hair dryer into an extension cord so that you can be more mobile.

Step 4: Race

You have probably guessed it by now, but you are going to be trying to move the ping-pong ball through all of the clothes hangers. You can make a fun game out of it and see how fast you can do the course. Get a friend to do it too, and then you can have races. Change the course around and see what things make it more challenging.

This is a really fun way to demonstrate physics!