The light bulb
The invention of the light bulb transformed our world by removing our dependence on natural light, allowing us to be productive at any time, day or night. Several inventors were instrumental in developing this revolutionary technology throughout the 1800s; Thomas Edison is credited as the primary inventor because he created a completely functional lighting system, including a generator and wiring as well as a carbon-filament bulb like the one above, in 1879.
As well as initiating the introduction of electricity in homes throughout the Western world, this invention also had a rather unexpected consequence of changing people’s sleep patterns. Instead of going to bed at nightfall (having nothing else to do) and sleeping in segments throughout the night separated by periods of wakefulness, we now stay up except for the 7 to 8 hours allotted for sleep, and, ideally, we sleep all in one go.
It’s one of the most famous discovery stories in history. In 1928, the Scottish scientist Alexander Fleming noticed a bacteria-filled Petri dish in his laboratory with its lid accidentally ajar. The sample had become contaminated with a mold, and everywhere the mold was, the bacteria was dead. That antibiotic mold turned out to be the fungus Penicillium, and over the next two decades, chemists purified it and developed the drug penicillin, which fights a huge number of bacterial infections in humans without harming the humans themselves.
Penicillin was being mass-produced and advertised by 1944. This poster attached to a curbside mailbox advised World War II servicemen to take the drug to rid themselves of venereal disease.
About 1 in 10 people have an allergic reaction to the antibiotic, according to a study published in 2003 in the journal Clinical Reviews in Allergy and Immunology; even so, most of those people go on to be able to tolerate the drug, researchers said.