Thomas levitates a ping pong ball
Thomas wrote to me specifically as he wanted to show me his favourite science experiment, the levitating ping pong ball.
To do this Thomas brought a hairdrier, a ping pong ball and his little sister Annaliese.
We lay on the floor and Thomas turned on the hairdrier, he then carefully balanced the ball so that the upward pressure from the hairdryer balanced the downward force of gravity. This kept the ball levitating and Thomas was obviously very skilled at this trick as he was able to angle the hairdryer and it stayed levitating!
The science part of this is based on the Bernoulli principle which states that fast moving air is at a lower pressure than slow moving air, so the airstream from the hairdryer is at a much lower pressure than the air around it. A ball that is smaller than the diameter of the airstream can therefore be balanced within it and if the ball starts falling out of the airstream to one side then the higher pressure of the air outside the airstream will push the ball back into the centre.
Luckily if the ball fell off, we also had Annaliese to help as our ball fetcher :)