The Secret Life of Machines

A Scottish chemist called Joseph Swann tried passing electricity through fine wires (filaments) to make them glow white hot in 1860. Despite enclosing them in bulbs and pumping out the air, they quickly broke or blackened and Swann abandoned the idea. 17 years later, finding a better vacuum pump, he tried again. With no air left inside, the filament light bulb became a practical proposition. Episode Contents: Models: Some lightbulbs made by removing the air from milk bottles and adding graphite filaments powered by a welding power supply. Various experiments with phosphors. Machines: "Magical" bulbs by Rex. Guests: Some early arc lights. Decorative experimental florescent tubes from the 1860's. A range of modern lighting sources and how their spectrums look. Films: Ancient lighting cartoon. A wacko british lightbulb ad. Extro: Say it in lights.