The light bulb, a brilliant invention, by Tomás Unger

For most people, entering a dark environment and “turn on the light”Is a routine act. Nor do we think that behind this act is one of the greatest achievements of human development, which required important scientific advances.

Our species, ‘Homo sapiens’, is eminently diurnal. Even on clear nights with a full moon we see much less than an owl or a cougar. At night we were prey and not the top of the food chain.

This first great leap was given with control of the fire. Its domestication – the ability to create, control and use it – was perhaps the most important step in the development of our species, since it drastically changed the limitations of food, protection and demographic expansion. ; its heat also allowed to inhabit regions colder than the tropics; and its light opened the doors to nocturnal activities and to occupy caves, which gave shelter and security.

The oldest evidence of controlled use of fire dates back almost a million years, among close ancestors of the ‘a wise man’, which we describe in recent pages. There is evidence of its sophisticated use – for example, for animal control or to produce rock art – dating back around 50,000 years. like the candles and oil lamps of ancient Egypt and Mesopotamia.

“Two factors were crucial to achieving a viable light bulb: a durable, inexpensive filament and a vacuum glass package.”

–The other great assault–

After the control of fire and the development of agriculture, the next exponential leap in the advancement of human beings was the management of another form of energy: electricity.

Although its natural manifestation was known since time immemorial – through lightning and static electricity – its scientific study and manipulation only occurred in the 18th and 19th centuries.

(1778-1829), considered the father of electrochemistry. This had as resistance a filament of platinum, a metal with a high melting temperature that glows when an electric current passes. This bulb was not practical, as it generated little light and did not last long; however, he succeeded in demonstrating the principle of resistance incandescence.

Davy’s invention was experimented with for several decades, using various materials as filaments. Two factors were crucial to achieving a viable light bulb: a durable and inexpensive filament and a vacuum glass package. Placing a filament in an oxygen-free vacuum, protected by a glass bulb, prevents it from igniting combustion. It should be noted that the filament can reach hundreds of degrees.

-Popularization-

By 1880, two inventors had succeeded in producing useful versions of light bulbs: Joseph Swan in England and Thomas Edison in the United States. The light bulb Swan used a charred cotton filament. With his version he managed to illuminate a street in 1879 and the interior of a theater in 1881.

Edison’s light bulb initially used carbon and platinum filaments, but a carbonized bamboo filament allowed for a much longer life: e. This version was first installed in a commercial building in 1880 and on a ship the following year.

Edison acquired the patents and allied with Swan to secure markets in the US and Europe. While Edison developed the generating sources of electricity and the networks to distribute it, other inventors were perfecting the electric light bulb with new materials and processes.

“The electric lamp was invented in 1802 by the English chemist Humphry Davy, considered the father of electrochemistry.”

-Effectiveness-

A major improvement was the switch to tungsten in the filaments, patented in Hungary by Sándor Just and Franjo Hanaman in 1904, and massively marketed seven years later.

This invention was enhanced in 1913 by filling the bulb with an inert gas, which does not burn or oxidize the metal and doubles the luminosity of incandescent metal.

While the luminosity of the incandescent light beam has improved over a century, the bulb with metal filament and inert gas has failed to overcome an important limitation: 95% of the electrical energy that passes through the filaments is converted into heat and only 5% is translated into visible light. 95% of energy is wasted.

, but the cost of the energy it consumes is greater than that of its production. Generally, its source of energy contributes to climate change. This has led to the development of other types of light bulbs.

On a next page we will explain the development of fluorescent light, thanks to the discovery of the emission of light from a material when irradiated with another type of energy. We will also discuss the rapid evolution of LED (Light Emitting Diode) lamps.

While fluorescent lamps are more efficient, they contain toxic materials and emit ultraviolet light. These are major disadvantages compared to LED technology, which reduces personal and global consumption of Energy.

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