Build-at-Home Missions

Rotor's Balloon Hovercraft

Build a hovercraft from an old CD and a balloon that glides on a cushion of air.

Print this sheet

Builder handle: ____________________   Date: ____________

Materials

• ☐ An old CD or DVD
• ☐ A pop-up bottle cap (sports bottle top)
• ☐ A balloon
• ☐ Strong glue or putty (with a grown-up)

Steps

1. Seal the cap. Glue the pop-up cap over the CD's center hole so no air leaks around the edge. Let it dry. ☐
2. Load the air. Blow up the balloon, pinch the neck and stretch it over the closed cap. ☐
3. Launch. Set it on a smooth table and pop the cap open. Give it a tiny push. ☐
4. Experiment. Time the glide. Try a bigger breath, a smaller one, a different surface. ☐

Finish line

Your hovercraft glides at least 1 meter (about 3 feet) from one gentle push.

Finish line: A 1-meter glide on a smooth surface.

What I built: ____________________________________________

One thing I fixed: _______________________________________

Check

1. Why does the hovercraft glide so easily?
   • ☐ The CD is light
   • ☐ A thin layer of air lifts it and cuts friction
   • ☐ The balloon pulls it
   • ☐ Magnets
2. Which change is a fair test of 'surface matters'?
   • ☐ Change the surface and keep everything else the same
   • ☐ Change the balloon and the surface together
   • ☐ Push harder
   • ☐ Use a new CD

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