Watch an old CD slide and hover on a cushion of air — it’s a real mini-hovercraft you can make at home in 5 minutes!
What You’ll Need
💿 1 old CD or DVD
🎈 1 balloon
🍶 1 pop-up bottle cap (from a sports drink — push-pull cap)
🧷 Hot glue (or super glue, with adult supervision!)
💨 Smooth surface (table or floor)
How to Build It
1. Glue the pop-up bottle cap to the center of the CD, covering the hole.
2. Make sure the cap is in the DOWN (closed) position when you glue it.
3. Let the glue dry completely (10+ minutes).
4. Blow up the balloon BIG — but don’t tie it!
5. Pinch the balloon neck so air doesn’t escape.
6. Stretch the balloon opening over the pop-up cap.
7. Push the cap UP (open).
8. Place on a smooth surface and gently push — IT GLIDES! 🛸
The Physics of Hovering
Air rushes out of the balloon, through the cap, and out the hole under the CD. This creates a thin layer of air UNDERNEATH the CD.
This air cushion:
1️⃣ Lifts the CD slightly off the surface
2️⃣ Eliminates most friction between the CD and the surface
3️⃣ The CD can now slide super easily — almost like floating!
Real-Life Hovercrafts
🚤 Real hovercrafts work the same way — air pumps push air down underneath, lifting the craft on a cushion of air.
🌊 They can travel over water, ice, mud, and sand
🪖 Used by military, search and rescue, and tourist boats
Experiments to Try
💨 Bigger balloon — does it hover longer?
⚖️ Add weight — put a small toy on the CD. Does it still hover?
🏎️ Race two hovercrafts — who can build the fastest?
🎯 Aim it — can you make it hit a target?
Why Does It Stop?
Eventually the balloon runs out of air. Without the air cushion, friction returns and the CD stops sliding.
Cool Hovercraft Facts
🚤 The largest hovercraft ever built carried 254 cars and 1,800 passengers!
🪐 Some Mars rovers use hover technology to land safely
🦟 Some insects basically ‘hover’ on the air pressure trapped under their bodies
💨 Modern air-hockey tables use the same principle on every shot
Float, glide, soar — physics is awesome! ✨
