"There are no mistakes, only opportunities."
Although this is one of Tina Fey's rules for improvisation, it can also apply to science. There are many inventions that we take for granted today that were born from "mistakes" or, to use a more positive phrase, "happy accidents."
Most people are aware of the stories about the discoveries of penicillin and Post-it notes (which are detailed below), but others are less well-known. For example, the concept behind the thermal ink-jet printer was discovered by accident in 1977 when an engineer at Canon in Tokyo, Ichiro Endo, rested a hot soldering iron on a syringe which held ink, causing the syringe to eject the ink. This concept eventually became the mechanism behind the first BubbleJet printer.
Scotchgard was discovered by Patsy Sherman, a chemist at 3M, while she was trying to develop a rubber that wouldn't deteriorate from exposure to jet fuel. When she was experimenting with a mixture, some of it accidentally dropped on the tennis shoe her assistant was wearing. The assistant was unable to clean the substance from her shoe, as it seemed impervious to water or alcohol, which fascinated Sherman. Sherman had stumbled upon a fluorochemical polymer that would repel water and oil from fabric. It was manufactured and sold as the first Scotchgard product in 1956.
In 1839, Charles Goodyear was looking for a way to fix the current flaws of rubber, which solidified and cracked in winter, and melted in the summer heat. But Goodyear discovered vulcanized rubber quite by accident when he happened to spill a mixture of rubber, sulfur and lead on a hot stove. The mixture charred and hardened, but the rubber was still malleable enough to be usable. He patented his vulcanization process in 1844, long before the age of automobiles. Years later, in 1898, the men who started the Goodyear Tire & Rubber Company named it after the man who made their business possible.
The adhesive behind Post-it notes was discovered in 1968 by Spencer Silver, a researcher at 3M Laboratories, who was actually looking for a stronger adhesive than what was currently available. Instead, he found a weaker one, an adhesive that stuck to objects but could be pulled off without damaging them or leaving a residue. A few years later his colleague at 3M, Art Fry, spread the adhesive on small pieces of paper to mark and re-mark his place in his choir hymnal. When he started using the small pieces of paper at work, colleagues came by to borrow some, and the Post-it note was born.
Probably the most important "accidental" discovery was penicillin. It was discovered in 1928 when Sir Alexander Fleming, a Scottish biologist who was studying the bacterium staphylococcus, left his petri dishes stacked on a bench while he went on holiday. When he returned, he noticed that a mold in a discarded petri dish (which he identified as Penicillium notatum) was growing in such a way that it dissolved all the bacteria around it. It wasn't until the 1940s, however, that the antibiotic agent was isolated and put to medicinal use.
Such "happy accidents" are continuing, and are likely to continue, into the future. In 2003, Jamie Link, a graduate student at the University of California at San Diego, discovered "smart dust" — programmable silicon particles — when a silicon chip she was working on exploded. She noticed that the small pieces still maintained their properties as sensors. Smart dust has uses and potential uses in medicine, pollution monitoring, equipment monitoring, and even bioterrorism surveillance. Although the concept had been researched since the 1990s by others, Link's unexpected discovery earned her the top prize of $50,000 at the Collegiate Inventors Competition in 2003.
Louis Pasteur said, "Chance favors the prepared mind." When scientists are open-minded to seeing all the possibilities in front of them, especially those they weren't looking for...that is when scientific magic happens.