How do neon lights work? — MT, Cement City, MI
A neon light uses a high voltage transformer to place electric charges on the wires at each end of a neon-filled glass tube. One end of the tube receives positive charges and the other end receives negative charges. Since like charges repel one another, the vast numbers of like charges at each end push apart strongly and some of them leave the wire and enter the neon gas. Once they’re in the gas, these charges are draw quickly toward the opposite charge at the far end of the tube. As they travel through the tube, these moving charges pick up speed and kinetic energy but they occasionally collide with neon atoms as they travel and can transfer some of their kinetic energies to the neon atoms. The neon atoms retain this extra energy only briefly before getting rid of it in the form of visible light—the familiar red glow of a neon lamp. Overall, electric charges stream from one end of the tube to the other, frequently colliding with the neon atoms and causing those atoms to emit red light. If you look closely at a neon lamp, you’ll see that it is the gas itself that’s emitting the red light.