How Does a Lightbulb Work?
Light bulbs are one of the few inventions that have remained pretty much the same over the years. It's a fairly basic construct that makes use of electron currents to produce light. Its framework is designed to connect with a power source and move electrons through a bulb, using heat, gas and metal to produce a continuous stream of light. The basis for this design relies on how atoms behave when subjected to certain conditions.
The structure of an atom is made up of a nucleus, which contains neutrons and protons, and electrons, which orbit the nucleus. Electrons circle their nucleus in orbitals, which exist in levels and vary in distance from the nucleus. When atoms are agitated--either by applying heat or by colliding with one another--their electrons move from one orbital to another. As they relax and return to a normal state, the electrons return to their original orbitals. Whenever an electron drops down from a higher orbital to a lower one, energy is released. This energy is released in the form of light, or light photons. Light photons are what we see when a light bulb is turned on.
The shape and design of a light bulb all work to move electrons through and agitate them along the way. At the end of the bulb are metal contacts that connect with an incoming power source. These contacts are connected to two wires that run up into the bulb. The wires are attached to a metal filament made out of tungsten. The remaining space inside the bulb is filled with a gas called argon.
The power source provides the electric current that runs through the light bulb. The bulb makes the most of this current at the point where the current makes contact with the filament. The electrical current works to agitate the filament's electrons. As long as the current runs through the filament, electrons will continue to change their orbital positions and so produce the light that we see.
In the case of light produced by light bulbs, heat is the agitating force that causes electrons to emit photon energy. The heat is generated as a result of the electrical current running through the tungsten metal filament. Tungsten's tolerance for high temperatures is what makes it a good filament material; however, after a certain point, even tungsten will breakdown and begin to melt.
To prevent this from happening, one of the few improvements made to the light bulb's design has been the use of argon gas to occupy the space inside the bulb, as opposed to the airless space that occupied the first light bulb design. The use of argon works to prevent the filament from melting, as argon causes any stray tungsten electrons to bounce right back into place.
