Create a rubber band racer

Create a rubber band racer

Create a rubber band racer

Follow FizzicsEd 150 Science Experiments:

You will need:

Six ice-cream sticks (paddle pop sticks)

Three thin rubber bands

Two wooden kebab sticks

Two plastic drinking straws

Four plastic cups

Sticky tape (we used black insulation tape so you can see the joins more clearly)

Scissors

A sharp knife or metal screw (adult use only)

It’s easy to get the materials to make this rubber band racer!

Create a rubber band racer science experiment - materials needed
1

Create a simple square using your wooden ice-cream sticks, making sure that you overlap the corners for strength. Secure strongly with sticky tape.

2 Rubber band racer axle made of skewer and straw

“Attached straw near the corner of the wooden stick square.”

3

“Wooden square with straws and kebab sticks in place… see how the rubber band is able to attach easily?”

Using scissors, cut your straw into four small pieces and secure these near the corners of the square you created. Make sure that there is at least 20 mm of distance from the end of the square edges so that your axle can have its rubber band fitted more easily. Thread the two kebab sticks through the straws as shown below.

4 Create a rubber band racer science experiment - front triangle brace

Use the remaining two wooden sticks and one side of the ice-cream stick square, to create a triangular shaped front end for your rubber band racer. Make sure that the two wooden sticks form that a small ‘cross’ at the front of your racer. Make sure that you can hook your rubber band over the front easily. As before, you should overlap the wooden sticks and secure strongly with sticky tape.

5 Rubber band attachment to the rear kebab stick axle

“Rubber band attachment to the rear kebab stick axle.”

Attach your rubber band to the back axle by wrapping the rubber band over the kebab stick. Now feed the rubber band through the loop created. Avoid using large rubber bands – they bend the kebab stick axle and do not grip the axle very well.

6 Rubber band attachment on the front of rubber band racer

“Rubber band attachment on the front of rubber band racer.”

Gently pull the rubber band forwards and over the cross, you created on the front of your rubber band racer.

7 Kebab stick through the base of the plastic cup

“A Kebab stick through the base of a plastic cup on the rear axle.”

Get an adult to create a small hole in the centre of each of the four plastic cups so that the kebab stick can only just pass through the base of each cup, make the hole fit tightly around the kebab sticks. Use the scissors to cut down each cup so that they look like four small wheels. Attach the cup bases as shown below and add rubber bands around the outside to give the rear wheels some extra grip.

8 Rubber band racer

“Completed rubber band racer, ready for action!”

You’re done! You should be able to carefully pull back the rubber band racer and then let it go. And watch it move forwards!

Why Does This Happen

This science experiment applies multiple ideas in classical physics, all in one fun little STEM challenge!

Firstly, by pulling back the rubber band racer you stretch the rubber band, thereby storing energy, also known as potential energy.

When you let the rubber band racer go, the stored energy in the tension of the rubber band is released and is transferred to the rear axle, an application of the first law of thermodynamics. Also known as the Law of Conservation of Energy whereby energy cannot be created or destroyed in an isolated system.

As the rear axle spins, the rear wheels grip the floor and push backwards which then sends the rubber band racer forwards! A classic way of demonstrating Newton’s 3rd Law of motion which states that for every action there is an equal and opposite reaction.

Variables to try

Try different floor surfaces… is carpet better than tiles for example?

How far will the car travel if you pull it backwards set distances (is the relationship linear?).

Does a different size rubber band make the rubber band racer go further?

Can you create a different wooden stick arrangement to add another rubber band to the racer? Does this make a difference to the speed and final distance achieved?

Learn more!

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