The higher pressure outside the ball pushes towards and holds the ball in place. Once the tube is placed over the ball and the high pressure is removed, the ball is shot upwards. It hangs motionless which I explain as anti-gravity. All that's in the box is a small fan that is set to blow upwards. There is another version of this demo that is sometimes seen in department stores where a leaf blower holds a beach ball in place over an isle.
More power means heavier objects can be suspended in air.
Another variation of this demo can be done with a leaf blower and a roll of toilet paper held on a wooden dowel or broomstick handle. By aiming the blower over the roll you create lower pressure above it lifting the paper which begins to unroll rapidly. Index of Activities . This activity is featured in Future Flight Hawaii , a K-12 Education Project of Hawaii Space Grant Consortium. FEB 27 2001.