Ping Pong Hair Dryer

Today my class tried an experiment to learn about gravity and force.
The gear we needed was a hair dryer and some ping pong balls.
First we made predictions for what will happen if we put a ping pong ball on a running hair dryer. Mine was that the ball would float and then fall off. We flicked the hair dryer one and put the ping pong ball on. It kept bobbing all around the place. It stayed on until we turned it off. So I was right about it floating but not it falling.
It is caused by the force of the hair dryer fighting against gravity. The gravity causes it to move around and not go up high. But the hair dryer keeps it up. It doesn't fall because of the amount of air surrounding it is bigger than the ping pong ball.