How do neon lights create different colors?
user
Neon lights are actually made from glowing gasses, such as neon, argon, and mercury vapor.  They shine by means of an electrical charge across a sealed glass tube filled with these gasses.  The precise colors produced by the different gasses are determined by the type of gasses and the precise frequency of the electrical charge passed through them.  Common colors produced by neon include red, blue, and green, although many other colors can also be achieved by varying the precise mixture of gasses.
assistant
How do neon lights create different colors?
user
Neon lights are a type of gas-discharge light which create their illumination by passing an electric current through a mixture of gases (containing neon or a similar noble gas).  Due to diffusion and collisions within the gaseous medium, these electrical currents stimulate fluorescent emission of various colors, including red, blue, and green, as well as the characteristic bright-blue color of pure neon gas.   Neon lighting is quite popular in signs and advertisements because of its vibrant colors and its iconic "neon glow".
assistant
How do neon lights create different colors?