The Photoelectric Effect

Description: This is a demonstration of the photoelectric effect. In the photoelectric effect, electrons are emitted from a metal when light is shone on it, providing that the photon energy is greater than the workfunction of the metal (ie, the amount of energy needed to rip an electron away from its atom). This demo is really fussy about humidity, so it often doesn't work, and the video is a cut from more than one take due to some misbehaviour with the experiment. But still, it worked better than it often does. Video posted for use under Creative Commons Licence - by-nc-sa