What does a potentiometer do?

What are potentiometers good for? We seem to have a lot of them in storage, but I for one have no idea as to their use. Googling was no help.


Basically, a potentiometer measures the rotational position of an axle, but unlike a shaft encoder, it can only rotate 265˚. It has mechanical stops in place to prevent rotation past that.
Basic info

So people generally use them on arms or catapults. Any system with a limited range(not a wheel). They are more helpful than encoders in many places because they give absolute location. An encoder says “I have turned 90 degrees since I was turned on” the robot being reset would wipe that value. A pot would say “I am at angle 23 degrees” the pots value is absolute while encoders are relative to initial position. Arms only care about location while drives care about movement.