Normally a ball falls when you let go of it. That’s because of gravity. But here the jet of air from the blower pushes the ball upwards and the ball floats.
An air jet bends when it meets a convex object and flows nicely around it. We call this the Coandă effect. So the air coming out of the blower flows smoothly around the ball, constantly pushing it towards the centre of the jet. This also works when you hold the blower at an angle. See if you can score!
Coandă effect with hairdryer
Did you know that you can also try this yourself at home with a hairdryer and a ping pong ball? The air from your hairdryer will flow nicely around the ping pong ball.
Turn it into a game! Set up a course with all kinds of obstacles and see how quickly you can move your floating ping pong ball to the finish. Then challenge your mum or dad: can they do it faster?