## Thursday 6 August 2015

### Science: Make your own Spool Car

This post was first written 1 June 2013 17:51

Did you ever wonder how a wind-up toy works?

Well, if you open it up you will see all the components that make it up.  You will notice a spring inside too.  It looks more like a ribbon but it's still a spring as when it tightens up it stores potential energy that when released it is what moves the wind up toy!

Potential energy
Potential energy is stored energy that is ready to be used.  There are many different types of potential energy…  Gravitational potential energy, electrical potential energy, heat potential energy and there are more, like mechanical potential energy which we will be the first things we get hands on with in this chapter. When energy is stored up waiting to be used we call it potential energy.

When we wind up our toy we create potential energy.

Kinetic energy

When the stored energy, the potential energy, is released and used to do something, we call this kinetic energy.  Kinetic means movement, and this is because when energy is released it tends to make things move or something to happen!

When we let go, the potential energy is transferred to kinetic energy and the car moves along the table or the ground!

These are our spool cars...

They work in the same way as a wind up toy except our elastic bands are used in place of the spring inside our wind up toy.  We tried sitting them up so it looked like a propeller and we had it on its side when it turned into a spool car.

How do you make one? This is how we made ours...

You will need:
• A cotton reel
• An elastic band (best to have different shapes and sizes so you can experiment)
• A paper clip (try different sizes to see which works best)
• Sticky tape
• A pencil, pen or crayon
• Washers - something like these

What to do:

1.  Put a paper clip on an elastic band

3. Thread a washer through the other end of the elastic band, like this...

4.  Choose a pen, pencil or crayon and put it through the elastic band then twist it and twist it and twist it until it's tight.

Now you are ready to play.  Put it on the table and watch it go.

I have seen these all over the web, all made in different ways you could try experimenting with yours to see which works the best.
• You could try to stick down your paper clip with tape or Blu tack to see the difference to the way it works.  Does taping or sticking the paperclip with sticky tack improve the design?
• You could try one washer, two washers, more or none.
• You can try some dowelling like ours in different thicknesses or a pencil, a pen or crayon.  What works best.  Does the weight of what you use effect how well it works?
• How far can you make yours travel?  If you make two you can race them to see which is fastest.
• How strong is your spool car?  Could it climb over a mountain of lolly pop sticks?
• Try different elastic bands.  Different lengths, different thicknesses.

What makes the spool car move?

Like I mentioned at the beginning of this post, when the spring in the wind-up toy tightens it stores up potential energy that when released is what moves the wind-up toy.  The potential energy (energy that can be used at a later time) is turned into kinetic energy (energy from a moving object)!
The same thing happens when you twist the rubber band; when you twist your elastic band you're storing potential energy.  The potential energy turns into kinetic energy when the rubber band unwinds.
The paperclip that doesn't go over the sides of the spool turns the pool.  The long pencil, stick, pen or whatever it is you decided to use, next to the washer(s) does not turn because it is longer that the spool's diameter therefore  it is dragged across the surface (the floor or the table) and this is what makes the turning spool moves forward in the way it does.

I hope you have fun with more of An Ordinary Life's Experiments!

#### 1 comment:

1. Thanks for the reminder my grandad used to make these. Brilliant.Anita