This exhibit uses a powerful fan which can suspend a ball in an upward moving stream of air. When you try to pull the ball slowly out of the air stream one begins to notice the ball being sucked back in. If you then let go of it, it will oscillate back and forth without falling to the ground.

What's Going On?

When the ball is pulled partially out of the air stream, the air that is moving fast along the side of the ball exerts less sideways pressure on the ball than the still air in the room. An airplane wing is shaped so that the air moves faster over the top of the wing tan it does over the bottom of the wing. The lower pressure on the top of the wing produces a suction which holds the airplane up, or, more accurately, the high pressure on the bottom of the wing pushes the airplane up and balances the downward effect of gravity.