How to Make a Hovercraft from a Balloon and CD

Create a fun floating hovercraft using just a balloon, CD, and bottle cap in this easy science experiment for kids.

  1. Gather Your Materials. You'll need an old CD or DVD, a balloon (round ones work best), a pop-top bottle cap or sports drink cap, strong tape or hot glue gun, and a smooth surface to test on like a table or floor. Make sure the CD has a hole in the center - most do. If using a hot glue gun, adults should handle this part.
  2. Prepare the Bottle Cap. Take your bottle cap and make sure the pop-top is closed. If you don't have a pop-top cap, use a regular bottle cap and ask an adult to poke 4-6 small holes in the top with a nail or drill. The holes should be tiny - about the size of a pin. These holes will control the air flow that makes your hovercraft work.
  3. Attach the Cap to the CD. Place the bottle cap over the hole in the center of the CD, with the pop-top or holes facing up. Secure it firmly with strong tape, wrapping the tape around the cap and onto the CD surface. If using hot glue, have an adult apply it around the base of the cap. Make sure the seal is airtight - any air leaks will prevent your hovercraft from working properly.
  4. Add the Balloon. Blow up the balloon and pinch the neck closed with your fingers - don't tie it yet. While pinching it shut, stretch the balloon neck over the bottle cap. Make sure it fits snugly. The balloon should be sitting on top of the cap, ready to release air down through the holes when you let go.
  5. Test Your Hovercraft. Place your hovercraft on a smooth, flat surface like a kitchen table or hardwood floor. Open the pop-top (or simply release your pinch if using a punctured cap) and gently push the hovercraft. It should glide smoothly across the surface with minimal friction. The air from the balloon creates a cushion underneath the CD, allowing it to hover just slightly above the surface.
  6. Troubleshoot Common Problems. If your hovercraft isn't working, check that the bottle cap is sealed tightly to the CD with no air leaks around the edges. Make sure your holes aren't too big - they should create a steady, gentle stream of air, not a rush. Try different surfaces - very rough or carpeted surfaces won't work well. The balloon should deflate slowly, not all at once.