Welcome to Brainstuff from house stuff works dot com where smart happens. Hi Am Marshall Brain with today's question, what is the difference between a fluorescent light and a neon light? A neon light is the sort of light you see used in advertising signs. These signs are made of long, narrow glass tubes, and these tubes are often bent into all sorts of shapes. The tube of a neon light can spell out a word, for example. These tubes emit
light in different colors. A fluorescent light, on the other hand, is most often a long, straight tube that produces white light. You see fluorescent lights and offices, stores, and some home fixtures. The idea behind a neon light is simple. Inside the glass tube, there is a gas like neon, argon or crypton at low pressure. At both ends of the tube, there are a metal electrodes. When you apply high voltage to the electrodes, the neon gas ionizes and electrons flow
through the gas. These electrons excite the neon atoms and cause them to emit light that we see. Neon emits red light when energized in this way. Other gases emit other colors. A fluorescent light works on a similar idea, but it has an extra step. Inside a fluorescent light is low pressure mercury vapor. When ionized, mercury vapor emits ultraviolet light. Human eyes are not sensitive to ultraviolet light, although human skin is. That's how we get sunburns and
sun tans. Therefore, the inside of a fluorescent light is coated with a phosphor. A phosphor is a substance that can accept energy in one form and emit energy in the form of visible light. In a fluorescent lamp, the phosphor accepts the energy of ultra violet photons and emits visible photons. The light we see from a fluorescent tube is the light given off by this phosphor that coats the inside of the tube. The light of a neon tube is the colored light that the neon adams give
off directly. Do you have any ideas or suggestions for this podcast? If so, please send me an email at podcast at how stuff works dot com. For more on this and thousands of other topics, go to how stuff works dot com and be sure to check out the brain stuff blog on the how stuff works dot com home page.