Tuesday 14 August 2018

5 Minute STEM Activity 15: The Spinner

Back in the old days, before plastic and huge toy companies filled our toy boxes, children had to make their own toys at home. Here's one we can all make which can also help us understand colours...

The Spinner
Can you make it hum? Hmmm? 

Large cardboard pieces - cereal box or pizza box is great. If you have no card then stiff paper works too.
A small plate - the cardboard must be at least as big as the plate.
Colouring pens or pencils
Ruler or a straight edge
A small book
A teaspoon with a plain handle
Sticky tack

1. Draw around a plate or something round to make a circle on the cardboard. The circle has to be at least 16cm across (the diameter). A normal saucer or small plate is about 19cm.

2. Cut out your circle. You can decorate it however you wish now, or later on.

3. Now you need to make a hole in the spinner. To work out where that goes, you need to find the centre. To find the centre of a circle we are going to use the Chord Method. This needs you to draw two parallel lines on your circle  - that sounds hard, but we can cheat a bit.

5. Take your book and place it on the circle, in the middle. Use the book as a straight edge and draw pencil lines on either side.

6. Draw a cross going from each corner to the opposite one. The middle of the cross is the centre of your circle and the spot where we need a hole.

8. The easiest way to make the holes is to ask an adult, but if you are old enough, you can poke a hole with a teaspoon handle. NEVER use scissors to jab holes in card. They can cause a lot of damage if the hole bursts open suddenly. Teaspoons are much safer and will do this job.

9. Decorate your spinner now if you wish. A spiral pattern like a snail shell is good, but you can try all kinds of patterns. If you use red, green and yellow, then you will be able to see what happens when you mix those 3 primary colours. We had red, blue and yellow - close. 

10. Cut a piece of wool, string or strong thread around 80-90cm long (about 4 times the width of your circle).

11. Thread the wool or string through the hole and tie it to make a loop. Slide the spinner to the middle of the string loop and add a blob of sticky tack to hold it in place.

12. Holding one end of the loop in each hand, spin your spinner one way, winding up the string or wool until it is really twisty.

13. Now pull the strings hard apart and the spinner should spin really fast to try and untangle the string. Relax your hands and the spinner starts to slow down because it isn't so desperate to unwind and stretch out. Hopefully it will go past and start winding itself up the other way. Once it has wound itself up, pull again to speed it up as it unwinds.

14. By pulling and releasing at the right time, you can learn to make the spinner spin for quite a long time, and if you are really lucky, it might even hum.

With our spinner decorated in equal amounts of blue, red and yellow, you will find that it looks almost white when it spins. That is because when you see things, you are actually looking at light bouncing off them, and mixing colours of light is very different to mixing paint.

If you decorated it with a spiral pattern, your spinner might seem to be growing or shrinking, depending on which way it is turning.

The spinner captures the energy you put into spinning it in the first place and releases it to turn by itself. As you spin, you twist the wool or string and as it gets more tightly wound, it is storing more and more energy. When it gets chance, it releases the energy by uncurling itself. This is Newton's Third Law Of Motion - every action has an equal and opposite reaction.  This is also the basics of how a pull-back toy car works, and with the addition of a balance wheel to control the speed of energy release, it's also how a wind-up watch works.

I'm taking tomorrow off to spend with my family, then I'll try and post another 5 minute STEM activity every other day until the end of the holidays. Time to catch up any you missed...

You can find all of my 5 Minute STEM Activities here...

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