Balloon Hovercraft
A balloon, a CD and a bottle cap make a puck that glides almost frictionlessly across a table.
Start building ↓The build
Mount the cap
Glue the bottle cap over the CD's centre hole, sealed airtight.
Attach the balloon
Stretch an inflated balloon's neck over the closed cap.
Release the air
Open the pop-top so air escapes downward through the hole.
Glide it
Push gently — the cushion of air lets it drift far.
Escaping air forms a thin cushion under the disc that lifts it just off the surface, slashing friction so a tiny push carries it a long way.
A closer look
The air film reduces sliding friction to nearly zero, so Newton's first law shows up clearly: the puck keeps moving until air runs out.
Variables to test
- 1 Time how long it glides with different balloon sizes.
- 2 Add weight on top — how much can the air cushion support?
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