­Yo­u see gears in just about everything that has spinning parts. Car engines and transmissions contain lots of gears. If you ever open up a VCR and look inside, you will see it is full of gears. Wind-up, grandfather and pendulum clocks contain plenty of gears, especially if they have bells or chimes. You probably have a power meter on the side of your house, and if it has a see-through cover you can see that it contains 10 or 15 gears. Gears are everywhere where there are engines and motors producing rotational motion.

In this edition of HowStuffWorks, you will learn about gear ratios and gear trains so you'll understand what all of these different gears are doing. You might also want to read How Gears Work to find out more about different kinds of gears and their uses or you can learn more about gear ratios by visiting our gear ratio chart.

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