Gears are used for transmitting power from one part of a machineto another. In a bicycle, for example, it's gears (with the help of achain) that take power from the pedals to th… See more

Let's think about cars. A car has a whole box full of gears—thegearbox—sitting between the crankshaft andthe driveshaft. But what do they actually do? A car engine makes pow… See more

Photo: Bicycle gears: Bikes have two sets of different-sized gears on the wheelyou pedal and the back wheel. Instead of touching directly and rotating in opposite directions, … See more

You might think gears are brilliantly helpful, but there's a catch. Ifa gear gives you more force, it must give you less speed at the same time.If it gives you more speed, it has to give you … See more