What makes a Neon Light Glow?

Have you ever seen a colorful glowing tube of light in a store’s front window or outside a restaurant, the glow is due to some noble gases which emits. These glowing tubes are called neon lights. Neon lights are commonly seen on advertising hoardings, outside shops, restaurants and cinemas. Their color is so distinctive that to most people the word “neon” has come to mean a dark pink glow, although neon is merely an elemental rare gas element.

The technology behind how a neon light works is very different from that of normal incandescent lights. Electroluminescence or the conversion of electricity directly into light is the operating principle of neon lights.

• A neon light consists of a glass tube filled with a noble gas at a very low pressure.
• Neon lights containing the other noble gases are also common.
• Neon is wholly colorless if placed in a normal flask, yet to glow of an eon light is visible even at night, so its color cannot be due to the way it interacts with light.
• Metal plates called electrodes are fitted to each end of the gas filled tube.
• When the neon light is plugged into an electricity supply, an electrical current flows through the tube between the electrodes.
• Gas discharge takes place and collisions involving mobile electrons generally elastic. They bounce like a ball off a wall.
• An extreme voltage ionizes the neon to form a plasma of Ne⁺ and e^-. Inelastic collision between Ne+ and neutral atom allow for the release of energy as visible light.
• Neon atoms are neutral, but ionization of the gas phase neon forms Ne+ ions, so the tube contains a mixture of electrons and ions.

Ne⁰(g) --> Ne⁺(g) + e^-

Thus neon light glows because they emit light under suitable conditions. All the light we see id a result of electrons jumping between electron shells. Subsequent relaxation of the electron releases a photon of light. It is this emission that we see as the bright glow of neon light.