What you need:
A balloon, A CD or DVD, Strong glue, Pop-top cap from a liquid soap bottle or water bottle, Tape, Drawing pin.
What to do:
1. Cover the centre hole of the disc with the tape. Poke 5-6 holes in it using the pin.
2. Use the glue to stick the pop-top cap over the centre of the disc. Let it dry.
3. Close the pop-top cap. Now, blow the balloon, and without letting the air escape, fit its mouth over the cap.
4. Place the disc on a table and push it. Does it go far?
5. Now, pop the cap open and then push the disc.
What happens?
When you haven’t popped the cap open, the disc does not go far. But once the cap is popped open, the disc actually skims over the table until the balloon deflates. Why?
When the cap is popped open, air begins to flow out of the balloon, under the CD. The disc is light enough to be lifted by this air flow. This creates a cushion of air between the surfaces of the disc and the table, reducing friction. Once the balloon deflates, the hover-loon’ is out of air and the disc stops.
Friction is the force that was bringing the disc to a halt when the cap was un-popped.
Hovercrafts operate on the same principle of reducing friction by employing air cushioning. To get a smoothly floating device, make sure your disc is not warped or cracked. There should be no holes, apart from the ones in the tape, that allow the air to escape. Also, the table or the floor needs to be smooth and without obstacles.
Picture Credit : Google
