Step-by-Step Instruction On How To Make A Bottle Rocket Car

So what is a bottle rocket car? They are a fantastic toy you can make from items you’d normally throw away. The basic ingredients for the rocket part are a plastic bottle, wine cork, bike inner tube valve, water and compressed air.

In short, we drill a hole through the cork, just wide enough to fit the valve through. Put some water in the bottle and tip the bottle so the water covers the opening of the bottle. Connect your bike pump to the valve and pump. The air enters the bottle and starts to compress. The pressure eventually builds to a level that blows the cork out of the bottle. As the water rushes out the bottle flies off, this is a beautiful example of Newton’s third law of motion.

If you’ve never seen or heard of Newton’s third law of motion before you can read it below, ever wondered about the science behind ollying a skateboard, this is it:

“Whenever particle A exerts a force on another particle B, B simultaneously exerts a force on A with the same magnitude in the opposite direction. The strong form of the law further postulates that these two forces act along the same line. This law is often simplified into the sentence "To every action there is an equal and opposite reaction."” – Sir Isaac Newton

If you don’t know who Sir Isaac Newton is, Google him, he was one very clever fellow.

When I first decided to make bottle rockets for kids club I was a little wary of launching rockets into the air with a bunch of five year olds……perhaps not the safest activity. So, how could I get around this? The solution was fairly simple, take the rocket design and develop it into a car. This way they can be shot off along the ground, nice and safe.

Are you ready? Time for the step by step instructions…….

What do you need?

The tools:

A drill

A sharp knife

An old bicycle inner tube valve

A bike pump, preferably with a long-ish hose

A glue gun – Very useful but not absolutely necessary

A vice – Again useful but not absolutely necessary

An adult to help with the tricky bits

A pair of wire snippers

The ingredients:

1 plastic drinks bottle, 600ml, 1l, 1.5l…..so long as the cork makes a good fit with the cap. The bigger the bottle the further it will go

1 wine cork

1 wire coat hanger

1 egg box

1 old bicycle inner tube

8 milk bottle tops

Most of the items you need to make the rocket car you should find hiding in the recycling bin. What we are going to do is reuse these items before we recycle them. Reusing is great, it means we can get new stuff for relatively effort and no new resources.

Please do not go chopping valves out of good inner tubes, that would be a real waste, instead go to your local bike shop with a big smile on your face and ask if they have any old tubes you can have. Willem from Thunderbikes in Wanaka very kindly supplied me with a heap of them. Thanks Willem!

The other item I went on the hunt for was wine corks. So put that big smile back on and pay a visit to your local restaurant and ask if they have any old wine corks you can have. They probably do. Jordy from Relishes kindly gave me a handful. Thanks Jordy!

Step 1

Cut the valve out of the inner tube with a sharp knife.

Step 2

Cut the cork in half using your sharp knife

Step 3

Get your drill, a drill bit the same size, if not a little smaller than the bike valve and drill a hole through the center of the cork. This is a good time to get an extra pair of hands, thanks Nev!

Step 4

Put the valve through the hole. Ensure the valve goes through smooth side and out of the rough side. This way, when we put the cork in the bottle the edge of the cork doesn’t destroy. If you don’t get it, trust me, it’s a good idea, stops your cork falling apart.

Step 4

Drill holes through the centre of your milk bottle caps

Step 5

Using the glue gun, glue the caps together

Step 6

Put holes in the side of the egg carton where you want your axels to go through

Step 7

Using the snippers cut a length of coat hanger long enough to pass through both wheels, the egg box and be able to be bent up at the ends to hold the wheels on

Step 8

Put the axel through the box, add the wheels and bend up the axel at either end. Now you should have the basis for your car

Step 8

Glue a wedge of some kind to the top of the box and then glue the bottle on top of the box, ensuring the bottle top is low down and sticking over the back of the box

Step 9

Put some water into the bottle

Step 10

Attach the bike pump to the end of the valve and push the cork into the end of the bottle

Step 11

Find an area you can launch the car on, remember get everyone to stand well away from the cars forward motion and have no one directly behind the car

Step 12

Start pumping and wait for the motion

Have fun out there, see you all on Saturday in Hampden.....