Rotary potentiometer

A rotary potentiometer is a special kind of knob that helps control things like the volume on a stereo or the brightness on a light. It has a little dial that you can turn around and around. Inside the knob, there is a special kind of wire that winds around in a circle like a spiral. This wire has a special power running through it that can go up or down depending on how far you turn the knob. This tells the circuit inside the stereo or light how much power to use, which changes the volume or brightness. So, when you turn the knob, you are telling the circuit to make things either louder or brighter. Cool, huh?