| The Chemistry of Fluorescence | ||||||||||||||||||||||||
| C100 Project by: Kyle Black & Julayana Tandujaja | ||||||||||||||||||||||||
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CONCEPT OF FLUORESCENCE Fluorescence: The process by which a variety of substances give off light; a form of electromagnetic radiation in which energy is absorbed. A lot of gases, solids, & liquids become fluorescent when exposed to radiation or electrically charged particles.UV rays, xrays, visible light and many other forms of radiation cause fluorescence. A fluorescent substance absorbs energy, thus causing the electrons in its atoms to become excited. Sometimes the electrons remain excited for only a very short period of time. Excess energy is then emitted as light. When the energy source is removed, the entire process stops. | |||||||||||||||||||||||
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THE FLUORESCENT LAMP The fluorescent lamp is a tube-shaped electric light used in many schools, factories, & offices. Fluorescent lamps are used in many schools, factories, & offices since they use less energy and produce efficient light and produce less heat than other lighting devices. The fluorescent lamp is a glass tube containing a tiny amount of mercury and a chemically inactive gas at a low pressure-the gas in most fluorescent lamps is argon. Inside the tube, the surface is coated with phosphors. An electrode (a coil of tungsten wire coated with chemicals) is located at the end of each tube. Inside a fluorescent lamp is a ballast, providing voltage to start the lamp and regulating the flow of current in the lamp circuit. | |||||||||||||||||||||||
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HOW A FLUORESCENT LAMP WORKS | A fluorescent lamp needs a starter and a ballast to operate. The starter switches electricity through electrodes at both ends of the lamp. The electrical current heats the electrodes so they can give off electrons. The ballast then sends a surge of current between the electrodes to form a stream of electrons, also called an arc, in the lamp. The lamp contains mercury vapor. The stream of electrons (the arc) knocks electrons in the mercury atoms out of their normal position. Upon the return of the elctrons to their normal position, the atoms give off invisible UV rays. The rays strike phosphor particles on the walls of the lamp, causing the particles to glow.
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