20 Things You Didn’t Know About Lightbulbs

The so-called Centennial Light, now hanging in the Livermore-Pleasanton Fire Department facility in Livermore, California, has been burning since 1901. It is a hand-blown bulb with a carbon filament, manufactured in Shelby, Ohio, in the late 1890s – and while it was originally bright enough to light up a room, it is now quite dim, about like a bathroom nightlight.

You may have heard someone who doesn’t seem very bright described as “a dim bulb.” There’s a good reason for that.

The Edison Memorial Tower, marking the site of the inventor’s Menlo Park laboratory, is a 131-foot-tall cement monolith topped by a bulb made of Corning Pyrex glass, measuring 13 feet and eight inches. It actually emits light.

In the popular cartoons of the silent era featuring Felix the Cat – considered the first major animated animal character – Felix’s thoughts or feelings were often indicated by some object appearing over his head. At some point, a lightbulb popped up when he had a good idea, and the metaphor stuck.

The celebrated “Wizard of Menlo Park” (New Jersey), whose many inventions included the photograph, the motion picture camera, and the storage battery, founded the Edison Electric Light Company in New York City in 1878, and on Dec. 31 of the following year, demonstrated the first incandescent lightbulb – which he claimed would make electricity so inexpensive that “only the rich will burn candles.”

But hold on a minute. A British scientist named Warren de la Rue invented an incandescent bulb in 1840, though it was too pricey to be viable. Numerous other scientists and inventors, including Henry Woodward, Humphrey Davy, Joseph Swan, and Mathew Evans also developed similar bulbs, though, like de la Rue’s, they were impractical for daily use.

The incandescent bulb, which was the familiar source of household illumination until the latter 20th century, will burn for only about 1,000 hours – a year on average with normal use.

Incandescent bulbs waste most of the energy that flows into them, dissipating it as heat – as anyone who’s tried to unscrew a lit bulb will know.

In 1962, Nick Holonyak, an engineer working for General Electric, demonstrated a laser diode that produced light – the direct ancestor of the now-familiar LED (light-emitting diode) bulb. Hewlett-Packard and Monsanto released commercial LEDs in 1968, but the technology didn’t really take hold until 1995, after many further improvements.

It may have taken a while to get up and running, but once the modern LED bulb was in common use, it proved to be a long-lasting trooper, burning an average of 25 times longer than its incandescent predecessor.

Not only does it last far longer than the incandescent bulb, it also converts energy to light far more efficiently. LEDs do generate some heat, especially when running in a closed space without ventilation, but it’s far less than incandescents throw off.

Contrary to popular belief, wattage isn’t a measure of brightness – it’s a measure of power consumption. A 100-watt bulb consumes twice as much energy as a 50-watt bulb, but while it will be brighter, it is not twice as bright.

About four billion lightbulbs are discarded in the U.S. alone each year – and that includes not just incandescents but also LEDs, fluorescents, and others. While they contain small amounts of recyclable material, the extraction process is considered more harmful to the environment than simply tossing the bulb out.

Incandescent and LED bulbs are just the start of it. The lightbulb family also includes halogen, fluorescent, compact fluorescent, high-intensity discharge, and specialty bulbs (like heat lamps, black lights, bug lights, etc.)

We tend not to be conscious of it, but the light streaming from incandescent bulbs flickers almost imperceptibly, which can have a subtle but unsettling effect on our concentration. Fluorescent lights can flicker more noticeably, which is particularly annoying, but LED bulbs produce a much steadier light.

You’d have to have really good hearing to notice it, but when incandescent bulbs are turned on, they make a faint buzzing noise – the sound of the filament heating up and expanding.

The U.S. Department of Energy has calculated that if only LED bulbs were used for light worldwide, there would be a need for 100 fewer nuclear power stations – about a quarter of those currently online.

Scientists from Columbia University, the Korea Research Institute of Standards and Science, and Seoul National University announced in 2015 that they had developed a lightbulb made of a graphene, a carbon allotrope (an element existing in more than one form) the thickness of a single atom, that produces visible light.

According to Guinness World Records, the word “SHUKRUN” – Arabic for “thank you” – spelled out with 8.015 LED bulbs was erected at Al Thumamah Airport north of Riyadh in 2021 by Flyadeal, a budget-priced Saudi airline.

Jokes involving the changing of a lightbulb were common for several decades. Many of them would now be considered offensive, playing off the supposed characteristics of various ethnic groups or professions. One inoffensive example: How many psychoanalysts does it take to change a lightbulb? None. The lightbulb has to want to change.