Thursday, September 27, 2012

Levitating ball

This is one of those experiments that I've seen in a number of books and kept passing up because it seemed like one of those experiments that looks like they should work but never do. The idea is that you use a hairdryer to "float" a light ball in the air. It works using Bernoulli's principle (the same principle behind airplane flight) - the fast air moving around the ball creates an area of low pressure, effectively acting to hold the ball in a tunnel. We were flipping through one of our books and Jr. scientist A found that experiment and asked to do it. I reluctantly got out the hairdryer, pointed it up and placed it on cool air, and gently placed the ball in the air stream. I was more than a little surprised to see the ball just float there on a cushion of air. Then Jr. scientist E did the next logical experiment - she nudged the ball. It moved a little and then moved back on its own to the center of the air stream like it was attached to a spring. That really got her excited. We all had a lot of fun with this experiment.