Electric bulbs are filled with inert gases. The actual type of gas used differs depending on the variety of the electric bulb. As the filament ignites, tungsten particles move away from the filament, resulting in the filament’s weakening and eventual breakage through time. But, the existence of inert gases within the light bulb aids in prolonging the electric bulb’s light span by delaying the tungsten’s evaporation process.
At the outset, traditional electric bulbs actually don’t no use gas. A vacuum was utilized instead, allowing the air to oxidize the filament once it starts to burn.
It is regarded that Thomas Edison invented the first vacuum-filled incandescent light bulbs. But, actual events were not actually like what we think of. There are several scientists who developed and devised the prototype of the incandescent bulb before Edison did. Joseph Wilson Swan, a British physicist, was one of them. Swan was inferred to secure the first patent for these electric bulbs. Soon enough, Edison and Swan joined together in producing incandescent bulbs commercially for the public.
However, it was soon found out inert gas atoms can recoil tungsten atoms back to the filament, which then restores the structure of the filament.
There are different types of gases used in an electric bulb. But, generally, only a single type of inert gas is utilized in a single lamp. What makes inert gases ideal is that they do not undergo chemical reactions when exposed to sets of given conditions. Moreover, they do not react with most substances, which is why they were regarded as inert or ‘inactive’ gases.
Those noble gases are usually used to prevent any chemical reaction from deteriorating a sample, such as in the case of the light bulb. The initial gas used, and still, the most common found in electric light bulbs, is argon. However, there are those lamps that mix argon with some part of nitrogen. Other electric bulbs utilize halogen, xenon, or krypton.
Aside from aiding in delaying the tungsten evaporation process from the filament, each type of gas has a unique advantage when used. For instance, xenon- and krypton-filled electric bulbs do not reach extremely high temperatures as argon-filled light bulbs would.
Moreover, xenon and krypton atoms are bigger than argon atoms, which makes them more efficient in recoiling the tungsten atoms to the filament. Thus, providing us with electric bulbs with longer life spans.
Xenon- and Krypton-filled light bulbs, however, entails a heftier cost than argon-filled bulbs. Xenon is considered to be the best option, but it is the most costly to use, which is why argon remained to be the most commonly used gas for producers.
Out of all the gas-filled light bulbs, halogen light bulbs have the longest life span. It can span about 2,500 hours or three years of use. However, safety remains a concern as halogen lamps can go extremely hot. Their glass also deteriorates through the time when touched often due to the presence of oil in our skin.
While Mercury is used in fluorescent bulbs, it is not incorporated in its gas form. Instead, the bulbs within are overlayed with mercury powder, which helps in the process of light production.
Due to the advancement of technology, there are types of light bulbs that no longer contain gases, such as LED lights. They are two-lead semiconductor light sources that emit light once electric current flows through them. Only those lamps that have a coated filament use a certain type of gas to function.
While inert gases slow the evaporation process of the filament, it cannot halt it entirely, and the filament will still deteriorate through time. The glass bulb’s filament will become less luminous efficient, darken over some period, until it is broken. The typical incandescent lamps that use filament and inert gases last around 1,000 hours.
- Incandescent light bulb (Wikipedia)