- an empty thread spool
- a 4-inch piece of cardboard
- a pencil
- a balloon
- Glue the empty spool to the piece of cardboard.
- Use the pencil to punch a hole in the cardboard, so it lines up with the center of the spool.
- Take a huge breath and blow up the balloon. Pinch the neck of the balloon, but don't tie it.
- Now, stretch the bottom of the balloon to the top of the spool. Let go of the balloon neck, and watch the hovercraft lift off!
How far can you make your hovercraft glide filling the balloon only once?