Gears by Chance

Gears are simple machines.  Some kinds of gears are: 40 tooth gears, 24 tooth gears, rack gears, worm gears, and cam gears to name a few.  There is also the driver gear and the followers gear.  You can find a gear in clocks and in  lego mechanisms.  A gear is a rotating machine part with cut teeth.  They may be on wheels or cylinders.  Gears have parts with teeth to change speed or direction.