How Does a Light Bulb Work?

Imagine a world without light. We would be stuck in the darkness and limited to completing the simplest tasks. Light might not be the first thing that comes to mind when discussing survival preparedness but not only is it a key to surviving life but also a tool that helps us succeed in dangerous situations. So, light is very important in our life.

Light can come from different sources. It can come from natural sources, like sun and stars and also from artificial sources, like fuel-burning light, electrical light, and chemical light. Nowadays, we rely on electrical light for everything. But, how’s life before the first light bulb invented? Before light bulbs invented, people mostly use candle and oil lamps. But they are dangerous because they will set the house on fire if they come into contact with something that can catch fire. They also emit carbon dioxide and less efficient than light bulbs. Luckily, Thomas Alva Edison made the first practical incandescent light bulb in 1879. Edison wasn’t solely responsible for this invention. Alessandro Volta and Humphry Davy’s early research and development contributed in the invention of light bulb we use now. This invention changed the world and our lives.

A light bulb is an electric light with a wire filament heated to such a high temperature that it glows with visible light (incandescence). The common light bulb consists of several parts, some of which you can see, and a few you can't. Thin glass forms the exterior of the bulb, called the globe. It contains the filament made from tungsten coiled coil which gives off light, a stem made from glass which holds the filament, support wires made of molybdenum which ensure the steady flow of electricity through the components of the light bulb, and a base made from vitrite and aluminium that screws into a socket, such as in a lamp or ceiling fixture. It also contains inert gasses formed of argon and/or nitrogen which you can't see. The parts function together as one of the most successful inventions of all time. Light bulbs come in a variety of different shapes. Eight different light bulb shapes you will find easily everywhere are arbitrary, bulged reflector, candle, globe, quarts reflector lamp, parabolic aluminized reflector, blown reflector, and twist. Light bulbs are also manufactured in a wide range of sizes, light output, and voltage ratings, from 1.5 volts to about 300 volts. Arbitrary-19 (A-19) is by far the most common one. The light bulb is widely used in household and commercial lighting.

A light bulb works by converting electronic energy into light energy. When the bulb is hooked up to power supply, an electric current flows through the wires and the filament. Then, free electrons zip along through the filament and continuously bump into the filament’s atoms. The energy vibrates the atoms, which means the current heats the atoms up. When the atoms in the filament heat up to 2200^oC, they will emit a good deal of visible light. That’s why the filament made from tungsten which has a high melting temperature. The process happens very quickly

The glass bulb has an important role in a light bulb. The glass bulb keeps oxygen away from the filament and helps enhance a bulb’s capability. If heated tungsten reacts with oxygen at such high temperatures, tungsten will catch on fire. In the first light bulbs, all the air was sucked out of the bulb to create a near vacuum so tungsten could not combust. But, this approach created another problem. At such extreme temperatures, the tungsten atom vibrates enough to detach from the atoms around it and flies into the air. In a vacuum bulb, free tungsten atoms shoot out in a straight line and collect on the inside of the glass. As more and more atoms evaporate, the filament starts to disintegrate and the glass starts to get darker. This reduces the life of the bulb.

So, to increase the life of the bulb, inert gasses, usually, argon and/or nitrogen are used in a modern light bulb. When a tungsten atom evaporates, it will collide with an argon/nitrogen atom and bounce right back toward the filament, where it will rejoin the solid structure. This gasses also prevent combustion because it won’t burn or react in any way with other elements, unlike oxygen. It also prevents the glass to get darker.

And that's how a light bulb works. That process happens just in a few seconds. Cheap, effective, and easy-to-use, the light bulb is still one of the most popular method of bringing lights indoor and extending the day after sundown.