However, if the ball is too heavy it will not float at all. A cross section of an airplane wing or a Frisbee may be useful. Show the audience the wing or Frisbee and how it is curved on the top side and flat on the bottom. Explain that, as they each travel through the air, the air that goes over the top must travel faster than the air that travels under them. Bernoulli discovered that the air that travels faster has lower pressure.
Lower pressure is just like a vacuum.
The ball is like the curved surface of the Frisbee or the wing. As air travels around the ball, the ball is pulled equally in all directions causing it to float. Also, a smaller version of the Bernoulli principle can be made at home. All you need is a straw, tape, and a ping pong ball or styrofoam ball. Fold one end of the straw and tape it so that no air can escape.