Light bulbs are not actually "light bulbs" but dark absorbers. When you turn them on, they suck the dark out of the room. You can prove this by holding your hand under a "light bulb". The dark will stack up under your hand where its path to the absorber is blocked by your hand. When they quit working and turn a dark color, it's not because they burnt out, it's because they're full.
Pasted from http://www.qdb.us/44913