Tyres
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When cars and bicycles were first invented they had very hard solid rubber tyres like the one shown above. Solid tyres made driving very uncomfortable on the bumpy roads. |
| Then someone came up with the idea of putting air into a hollow rubber tyre and things improved! The air acts like a cushion as you go over uneven roads making driving more comfortable. |  |
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The trouble with tyres with air in them is that they go flat if they are punctured by sharp objects. This is an old photograph of a man changing a wheel on his car after a puncture. |
Have you ever notice the tracks tyres make on the road, especially if they are going over snow or after going through water? Have a closer look at a bicycle tyre to look at the ‘tread’, that is the bumpy pattern on the rubber. The tread stops the wheels from slipping when the road is wet.
Try riding your bike or toy vehicles through some water and then look at the patterns they make on the ground.
To make your own tyre tread patterns collect some round cheese triangle boxes. Cut some shapes and glue them around the outside of the box to look like a tyre. Push a short stick or straw through the middle.
Have some poster paint ready in a shallow tray and roll your ‘tyre’ through the paint. Don’t get too much on it or the print will not be clear! Now roll the tyre across a large piece of paper and see what tread pattern you make.
You could try getting the class to ride their muddy tyres over very large pieces of paper or card to create different shapes.
Try printing the smaller tyres onto different coloured papers with contrasting poster paints. If the shallow trays of paint prove difficult then try sponging the paint onto the tread patterns instead.
Have a display of the different patterns and some photos of the vehicles which made them and invite people to match the tyre to the pattern.
