# Hovercraft & Friction Experiment

If you happen to have an old CD disc and a balloon, what will you do with it?

In our house, our first reaction was, “Let’s do a science experiment!”

“Sure”, I said.

I remember I’ve seen an experiment using these two items to make a balloon hovercraft.

But my daughter said we would need some strong glue (hot glue) and a special type of bottle cap which we didn’t have.

I’m not a big fan of complicated projects, especially ones that involve hot glue!

So I came up with a simplified version.

It doesn’t look as “professional” but it provides just as much fun.

### What you need

• CD disc
• unused balloon
• some sort of bottle cap that has an open/close mechanism
• packing tape

### Steps

1. Using packing tape, securely tape the bottle cap onto the CD. When you tug on the cap gently, there should not be a gap between the cap and the CD.

1. Close the cap’s opening.
2. Blow up the balloon and hold its opening with one hand.
3. With the other hand, wrap the balloon’s over the cap’s opening and then let go.
4. Place the hovercraft on a flat surface.
5. When you’re ready, push the cap open so the balloon can deflate through underneath the CD’s hole.
6. Give it a gentle push to set it off.
7. You just created a balloon hovercraft! It can slide across the floor fast and far.

### Why

Friction is the force created when two objects move across each other to oppose the movement.

An object gliding on the floor stops because of friction.

When friction is reduced, a gliding object moves faster, farther and for longer.

This balloon hovercraft can fly across the floor because air has less friction than the floor.

When pressurized air escapes from the hole on the CD, it creates a layer of air cushion beneath the CD.

So the hovercraft glides on air instead of the floor and it can go much faster and farther than if you just push a CD alone.

A real hovercraft and an air hockey game work based on the same principle.

A hovercraft uses blowers to produce a large volume of air below the vessel to allow it to travel at high speed.

An air hockey table produces a cushion of air on the play surface through tiny holes so that pucks can travel quickly and freely to allow you to score!