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# Bernoulli's hair dryer

### Transcript

Blow drier flier, on this moment of science.

Blow driers are a lot of fun when you're a kid. It's such a great feeling to have warm air blowing through your hair after a shower. Heck, even adults love it.

And you know what's neat about blow driers? They also show us something about physics. Here's a neat experiment you can do at home. All you need is a blow drier, and a ping-pong ball.

Take the drier and point it up. Now turn it on. Now place the ping-pong ball about a foot over the nozzle of the drier. Look at that! The ping pong ball floats in mid-air!

Okay, that's cool. But get this: once you have the ping-pong ball hovering over the drier, try tipping the drier to one side a little. You'll find that the ball stays hanging in the air even when the drier is tipped at an angle. It looks as though gravity is suspended!

What's actually happening, though, is called Bernoulli's Principle. Bernoulli's Principle says that fast-moving air has lower pressure than slow-moving air. So the fast-moving column of air coming off the blow-drier has less pressure than the air around it. The ping-pong ball bounces off the higher-pressure air in the room and stays inside the lower-pressure column of air coming off the drier. Even when tilted to the side!

See Bernoulli's Principle in action with an experiment at home!

Blow driers are a lot of fun when you're a kid. It's such a great feeling to have warm air blowing through your hair after a shower. Heck, even adults love it.

And you know what's neat about blow driers? They also show us something about physics. Here's a neat experiment you can do at home. All you need is a blow drier, and a ping-pong ball.

Take the drier and point it up. Now turn it on. Now place the ping-pong ball about a foot over the nozzle of the drier. Look at that! The ping pong ball floats in mid-air!

Okay, that's cool. But get this: once you have the ping-pong ball hovering over the drier, try tipping the drier to one side a little. You'll find that the ball stays hanging in the air even when the drier is tipped at an angle. It looks as though gravity is suspended!

What's actually happening, though, is called Bernoulli's Principle. Bernoulli's Principle says that fast-moving air has lower pressure than slow-moving air. So the fast-moving column of air coming off the blow-drier has less pressure than the air around it. The ping-pong ball bounces off the higher-pressure air in the room and stays inside the lower-pressure column of air coming off the drier. Even when tilted to the side!