Something sharp to punch a hole through the card, a pencil works well
Cotton spool
PVA or craft glue
Balloon
Flat table
What to do
Cut a 12 x 12 centimetre square from the cardboard.
Punch a hole in the centre of the cardboard the sa me size as the hole in the cotton spool.
Line up the hole through the cotton spool with the hole in the card and carefully glue the cardboard on top of the spool. Allow to dry for one hour.
Make a tight seal where the spool and cardboard meet with more glue. Make sure that there are no gaps where air can escape.
Cut out a circle of cardboard the sa me size as the top of the spool and glue it securely to the top of the spool. Allow the glue to dry completely.
Punch a hole through the cardboard cover into the centre hole of the spool. A hole should now be running through the paper, spool and cardboard with any obstructions.
Blow up a balloon and twist the neck to keep the air from escaping.
Stretch the balloon over the top of the cotton spool while still keeping the neck twisted.
Set the hovercraft on a level table and let go of the balloon. What happens?
What's happening?
When you let go of the balloon, the air in it tries to escape. The only way the air can get out of the balloon is downwards - through the hole in the spool. A cushion of air is forced between the cardboard and the table. Since the friction of the air against the table is less than the friction of the cardboard against the table, your mini-hovercraft can easily skim across the table. To experiment with this, try to push your hovercraft across the table without blowing up the balloon. It should be much harder to get it to move, because friction is stopping the cardboard sliding over the table.
It's fun to experiment with different sizes or types of cardboard and different sized balloons to come up with the most efficient hovercraft design. Try a piece of stiff plastic, such as an ice-cream container lid, instead of the cardboard. An old CD or a piece of Styrofoam also works well. You can also experiment on different surfaces - try carpet, concrete, water or dirt. A fun but messy experiment is to scatter talcum powder on top of an outside table. Which surface does your hovercraft move over quickest?
You could also try giving your hovercraft a skirt. Cut a tough plastic bag into strips along the edges of the base of your hovercraft. Make sure the plastic hangs down from the cardboard like a skirt. What happens to the hovercraft now?
Applications
Luke's landspeeder is not really a hovercraft. In Star Wars the landspeeder, along with most of the other transports, is oblivious to the law of gravity. They levitate freely and generate streams of charged particles to propel them. Luke's landspeeder is powered by a repulsorlift engine - a device that defies a planet's gravity. Since we are lacking the technology to build antigravity machines, a hovercraft seems to be the next best thing.
Hovercrafts travel just above the surface of land or water on an invisible layer or cushion of air. A hovercraft, also known as an air cushion vehicle (ACV), can travel smoothly, quickly - about 130 kilometres per hour over water - and efficiently.
The only problem with hovercrafts is that they can't stop very quickly, which makes them quite dangerous on land. Because of this, these vehicles are most often used to carry passengers or cargo over water. When the hovercraft reaches land, it does not need a special harbour; it is simply driven onto a beach where it can unload.
Make a tight seal where the spool and cardboard meet with more glue. Make sure that there are no gaps where air can escape.
Punch a hole through the cardboard cover into the centre hole of the spool. A hole should now be running through the paper, spool and cardboard with any obstructions.
Set the hovercraft on a level table and let go of the balloon. What happens?
