How to make a Hovercraft

You need a CD a push-up bottle top (the kind you can pop open and closed on a water bottle or a bottle of dishwashing soap) a balloon and superglue.

Superglue the bottle top right over the center of the CD (where the hole is) to make a valve. Now wait for the glue to dry! Keeping the valve CLOSED blow up a balloon and stretch the end over the valve in the middle of the CD. Place the hovercraft on a flat floor (not carpet). Let go of the balloon and pull the bottle valve to the open position. Watch it hover over the floor! Then do it again!