What is the gas inside fluorescent light bulbs?
In a fluorescent light tube, the gas that is causing emission of light is a small quantity of mercury vapor. Inside each tube is a small drop of mercury which provides the mercury vapor. The rest of the tube is filled with inert noble gas like neon or argon. The mercury vapor is the gas that emits ultraviolet light when the tube is turned on. The untraviolet light is absorbed by the white fluorescent coating on the inside of the tube, which then re-emit visible light. The presence of mercury is why fluorescent tubes are hazardous wastes. That’s why they say to be real careful with it. Mercurcy and mercury vapor are really bad on a person’s health.
