Why Does The AnalogRead Read a Non-Zero When The Sensor Is Unplugged

Greetings, basically I'm an arduino noob, first forum post and all but I found something quite pecuilar during my current project. I have a potentiometer that sends analog signals to the A0 port and the arduino then uses that value to write to an ESC and run a motor. But I digress the real mystery is when I remove my potentiometer from my breadboard, the arduino reads analog values ranging from 271 - 309 which then moves my motor. I was just wondering why, if there's no electrical connection there, where do those strange values come from.

Thanks In Advance Dudes

it is just "floating" as it has no reference. Use a 10K pull down resistor to GND to get a consequent zero