The element neon, symbolized as Ne, is a noble gas with atomic number 10. Under normal conditions, neon is a colorless and odorless gas. However, when an electric current passes through it in a discharge tube, it produces a distinct and vibrant reddish-orange glow.
The True Color of Neon
The reddish-orange glow of neon gas is a direct consequence of its unique atomic structure and the way it interacts with electrical energy. When a high voltage is applied across electrodes at each end of the tube, it creates an electric current that flows through the gas. This current causes electrons to collide with the neon atoms, transferring energy to them.
These energized neon atoms become “excited,” meaning their electrons temporarily jump to higher energy levels. The electrons quickly return to their original, lower energy levels. As they fall back, they release the excess energy in the form of photons. The specific energy difference between the excited and ground states of neon atoms corresponds to wavelengths of light that our eyes perceive as reddish-orange.
Understanding “Neon Colors”
The term “neon colors” often refers to a wide range of vibrant hues, including bright greens, pinks, blues, and yellows. This widespread use of “neon” as a descriptor for any vivid, glowing color is misleading, as only tubes containing actual neon gas produce the reddish-orange light.
Other bright colors seen in “neon” signs are achieved by using different gases or mixtures of gases within the glass tubes. For example, argon gas produces a lavender or blue hue, and when mixed with mercury vapor, it creates a light blue. Helium produces orange or pink, while krypton glows white-blueish or gray. Additionally, the inside of the glass tubes can be coated with phosphors, which are materials that absorb ultraviolet light emitted by excited gases (like argon-mercury mixtures) and then re-emit it as visible light of various colors.
Applications of Neon Light
The reddish-orange glow of neon is useful in various applications, most notably in signage. Georges Claude introduced the first neon sign in 1910, and these signs became widely popular for advertising and artistic displays. The ability to bend glass tubing into intricate shapes allows for creative and customized illuminated letters and designs.
Beyond large-scale signage, neon gas also has other applications. It is used in miniature neon glow lamps, which serve as small indicator lights in electronic equipment. Neon is also found in high-voltage indicators and lightning arresters, where its insulating properties and ability to conduct electricity once a certain voltage is reached are utilized. Additionally, a mixture of helium and neon gases is used in helium-neon lasers, which produce red beams for applications like barcode scanners and medical instruments.