Gears are toothed wheels which are interconnected to transfer movement from one shaft to another shaft. The speed at which the gears turn can be altered through changing the number of teeth. Gears can also be used to magnify a force or change its direction.
The first recorded use of gears was in 200 to 190 BC, when they enabled an ox-powered water-wheel to be developed. Soon gears were being used to drive various types of mills.
Today, gears are found in all kinds of machines, from motor vehicles and bicycles to simple egg whisks.
