High School Essay, 2030: 'Why We All Use CFLs Today'

Note: the contributor found this essay, yellowed and wrinkled, on the floor while calibrating his time machine. -- Ed.

When I was born in 2014, light bulbs were just starting to be used. Back then, they used instead something called an incandescent light bulb. They produced light just like a light bulb, but they were called incandescent because they were heated up so hot that they glowed yellow! I can just imagine my parents' surprise when they touched one of these. Yow, I burned my hand! It's really hot!

Of course, today people use light bulbs in their homes. But the real name for a light bulb is "compact fluorescent lamp" or CFL for short. Since all light bulbs are CFLs, I guess the right name probably was dropped, and they just kept the old name. Anyway, I'm going to tell you why all light bulbs today are CFLs, and about a different kind of light bulb that back in 2014 people thought might be used instead of CFLs.

It turns out that there was another technology back then, called LEDs, or "light emitting diodes." LEDs also produced light, just like real light bulbs. They were electronic devices. When you put power into them they generated light directly, without having to glow from the heat. They didn't have to glow red hot. They changed the electricity directly into light.

CFLs also change electricity into light. They make a charged soup inside the bulb called a plasma, and this plasma gives off light at 235 nanometers. (You can't see this light. Your eyes see only from 400 nanometers to 750 nanometers -- they don't see at 235 nanometers.) Then a material called a phosphor absorbs this 235 nanometer light, and that gives off light that is white. LEDs worked pretty similarly. They gave off light at 475 nanometers (this is like blue light). They also used a phosphor to absorb this light, and they also gave off white light.

LEDs sound kind of similar to CFLs technically and maybe even seem simpler, so how come LEDs weren't more popular? It turned out that LEDs were way too expensive. In 2014 you needed several LEDs to make a decent light bulb, and an LED cost two dollars. Then they still had to have electronic stuff to connect the LED up to the electricity. In the end, LED bulbs in stores cost something like five dollars, while real light bulbs cost only one-fifty. Why would people pay more money than they had to? It turned out that no one did, and so LED light bulbs didn't make it.

Of course, there are still some LEDs around, like the OLEDs backlighting my iPhone 11. But for general lighting, everyone uses compact fluorescent light bulbs. No one even remembers that LEDs were once thought to be the next kind of light bulb. Shows you what a lot has changed since I was young.

Teacher's Comments:

I think this is a little simplistic. You might mention that LED light bulbs did eventually get to be as inexpensive as CFLs, but that by then everyone had already gotten used to CFLs, and so LEDs never caught on. Next time, please tell your iPhone to turn on "relevance checking." There are things in here that don't belong.