Neon (Ne) is the most common noble gas used in neon signs. The term "neon signs" comes from its frequent use as a lighting agent.
Neon is a highly inert gas, making it easy to use. Its distinctive red glow is also eye-catching, making it ideal for signs and lighting. Tubes of plastic or glass are filled with neon, and as electricity passes through, the discharge excites the neon ions and pushes them into a higher energy state. The energy expended by the ions as they move shows up as a bright red color. The tubes can be twisted depending on design.
Aside from lights made from pure neon, other colors can be created when combined with other noble gases and elements. For instance, neon mixed with mercury creates a light blue glow.