Gears are used to change speed in
rotational movement. In the example above the blue gear has eleven
teeth and the orange gear has twenty five. To turn the orange gear
one full turn the blue gear must turn 25/11 or 2.2727r
turns.
Notice that as the blue gear turns clockwise the orange gear turns
anti-clockwise.
In the above example the number of teeth on the orange gear is not
divisible by the number of teeth on the blue gear. This is deliberate.
If the orange gear had thirty three teeth then every three turns
of the blue gear the same teeth would mesh together which could
cause excessive wear. By using none divisible numbers the same teeth
mesh only every seventeen turns of the blue gear.
