Hovercraft... The Levitating Car
You Will Need:
  • Compact disc (an old scratched up music CD or one of the computer CDs that come free in the mail)
  • Thread spool or 35mm-film canister
  • Glue
  • Balloon
  • Smooth tabletop

What to do:

  1. If you are using the film canister, have an adult poke a pencil-size hole in the middle of the bottom and the middle of the cap of the canister. Make sure the cap on tightly.
  2. Cover the top of the spool, or cap of the canister, with a medium-thick coat of glue.
  3. Line up the hole in the CD with the hole in the spool. Glue the CD to the spool. Make sure that you have used enough glue so that no air will escape from between the spool and the CD. Allow some time, about an hour, for the glue to dry completely!!!
  4. Place the hovercraft with CD on the tabletop and give it a flick to propel it across the table. Measure and record the distance traveled. Repeat this twice more.
  5. Blow up the balloon. Twist the neck of the balloon, about 1 inch up, to keep the air from escaping.
  6. Keeping the balloon twisted, stretch the neck of the balloon over the spool.
  7. Still keeping it twisted, set the hovercraft on a level table.
  8. Let go of the balloon and give the hovercraft a gentle flick. Measure and record the distance traveled. Repeat this twice more.
  9. Did the hovercraft travel further with or without the balloon? Why?
A hovercraft is a vehicle that travels, suspended, on a layer of compressed air just above land, or even water. A flexible sleeve called a 'skirt' goes around the perimeter of the craft to hold air underneath, creating an area of high air pressure that lift the craft up. The compressed air also serves as an invisible cushion that eliminates almost all friction between the vehicle and the surface. A fan attached to an engine generates the cushion of air.

Commercial hovercraft can carry passengers, vehicles, and freight. Some can travel as fast as 80 miles per hour.

How do drivers steer their hovercrafts? Rudders, like the type used on aircraft, control some hovercrafts. Other hovercrafts use 'puff ports' or dual thrust fans that turn on and off to turn in the direction desired. These thrusts of air are similar to the way canoers change directions by moving water around with their paddles.
             back