Balloon Hovercraft

Floating on a cushion of air.

 

 

 

Category - Force & Energy

Key Idea - Friction

 

Purpose - This can be used when teaching the concept of friction, and how to lower it's effects. 
Nature -  Demonstration or Experiment
Materials -  An unwanted Compact Disc, lid from a pop top drink bottle, super glue, balloon, toilet paper roll.

This is the basic components of the hovercraft assembled and ready to inflate. 
Method - 
  1. Carefully glue the pop top lid over the hole in the centre of the CD. It will work best if the silver side is down and you use lots of glue. The glue must not fill the hole in the CD.
  2. Once dry place the balloon over the top on the pop top lid.
  3. Inflate the balloon by blowing through the hole in the CD. Once full, use close the pop top lid to prevent air escaping.
  4. Cut the toilet paper roll lengthwise and trim to an appropriate height to form a collar under the balloon, to hold it upright. Place this around the base of the balloon and pop top lid.
  5. Pop the lid open to allow air to flow through the lid to the underside of the CD, and give the hovercraft a gentle push.

The hovercraft with inflated balloon and collar to hold balloon upright.

Safety - Nil
Explanation - The escaping air has to push out from under the CD which lifts the hovercraft above the ground slightly, allowing it to move with very little friction. This is the exact same principle used by real hovercraft.
Notes - This is a very quick demo if you already have the hovercraft made up. It is also an easy practical; the longest part is waiting for the glue to dry (it is best left over night)

The hovercraft will still work without the toilet roll collar, however the balloon tends to flop sideways and drag along the ground, creating friction.