A burning candle has a soft, glowing flame that gives off light. But when you turn on a light bulb, there is no flame. So how does a light bulb give off light?
When the light is on, electricity runs through a tiny wire inside the bulb. This makes the wire hot. Like everything else, the wire is made of tiny bits of matter called atoms. As the wire in the light bulb gets hot, the atoms soak up energy. Pretty soon, the atoms have soaked up all the energy they can hold. Then they begin to throw off the extra energy as light.
Compact fluorescent lights or lamps (CFL’s) are twisted glass tubes filled with gas. CFL light bulbs give off light when electricity passes through the gas, causing the tubes’ coating to glow.
Some bulbs produce light when electricity flows through tiny devices called light-emitting diodes (LED’s). LED’s are used in remote controls, billboards, traffic lights, street lights, and even car headlights.
Picture Credit : Google