Before LED strips lit up the bedrooms of kids around the globe, the world was dazzled by another glowing multi-colored display. Neon lights of all shapes and sizes were popular in the 20th century to create signs to advertise products and businesses. Cities such as Las Vegas still shine brightly with the glow of neon.
A rather unassuming chemical element is the key to these brilliant displays. Colourless and odourless, Neon (Ne), sits amongst the noble gases on the periodic table of elements. As a noble gas it is very stable and has little reactivity to other elements.
The word neon comes from the Greek word Neos, or ‘new.’
Neon is rare here on Earth, but it is the fifth most abundant element in the universe. It is created in massive stars where pressure within the star is so great that it fuses carbon atoms into neon atoms. Here on Earth, neon is extracted from air that has been compressed and then cooled to form liquid air. The liquid air is then warmed up in a fractional distillation column. Gases within this device separate, turning from liquid to gas, depending on their boiling point. Neon makes itself known at its boiling point -246 degrees Celsius.
The neon light was first developed in France in 1902 by chemist Georges Claude. Also known as a cold cathode fluorescent lamp (CCFL), it consists of a sealed glass tube filled with neon with an electrode at each end. Enough electricity passes through the tube to ionize the neon atoms, removing an outer electron from them which then bounce around the tube colliding with other electrons. As the neon atoms recapture their electrons, energy is released as a photon (light).
A balloon filled with neon would float, but would rise slower than helium, the only gas that is lighter than it.
You see neon signs and lights in all colours of the rainbow, but the element neon is actually only responsible for the colour orange-red. Each of the noble gases produces a signature colour and can be used in the glass tubes. Helium, for example, glows pink while krypton is green, and argon is blue. And gases can be combined like paints on a palette, to produce intermediate colours.
Neon’s uniqueness means it can be of many uses. It’s found in the taillights of cars and front lights of trains as well as in the signs and signals that direct them along their routes. It can be found in the lasers of surgeons operating on eye injuries. It is also the gas within lightning arresters, those rods that divert lightning safely to the ground rather than directly into a building.
In its liquid form neon can be used as a cryogenic refrigerant, meaning its capacity to keep something cool is very high. This means it is ideal for preserving biological specimens, for medical and scientific research.
Considered to be non-toxic, neon is a simple asphyxiant which can cause dizziness, nausea, vomiting and loss of consciousness if inhaled.