Kathryn from Ardingly College Junior School described the way the cogs move:If you turn the cogs to the right they will move away from each other, but if you turn them to the left they will move towards each other. This is the same no matter which sized cogs you have.
Ollie and Tom, also from Ardingly College Junior School, put this a bit differently:One cog moves one way and the other the other way.
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