Everyone loves the story of penicillin: One day, pharmacologist Alexander Fleming returned from a two-week vacation to Scotland, only to peer into a moldy Petri dish and find the world’s first antibiotic. We love this story because it’s such a neat discovery, and also because it’s so rare. Typically the process of science is molasses-slow, far more tedious than transcendent. Breakthroughs take years, even lifetimes, of work, and are usually less about individual genius than about building upon a collective foundation of knowledge.
Sometimes, however, a commonly held understanding really is overturned in one fell swoop. As science fiction writer Issac Asimov is said to have quipped, the exclamation that heralds such discoveries isn't really “Eureka!” but “That's funny.”
There's no doubt that the history of science is filled with fortuitous finds and moments of unanticipated connection. Chinese alchemists are said to have invented gunpowder while testing a prescription for eternal life; Archimedes discovered principles of volume while sloshing about in his bath. Hard evidence for these ancient tales is lacking, but a host of more recent scientific breakthroughs were definitely the result of happy chance—coupled with the fact that they occurred before watchful eyes and scientific minds trained to observe them.
Research engineer Richard Gaughan has studied centuries’ worth of just such discoveries for his book Accidental Genius: The World's Greatest By-Chance Discoveries. As he tells Smithsonian.com, calling these discoveries “accidental” can be a bit misleading. “When preparation, opportunity, and desire come together,” Gaughan says, “the result can be an accidental discovery that changes our understanding of the world.” Here are seven scientific moments that changed the world.
Newton's Law of Universal Gravitation (1666)
The story of Issac Newton's apple-driven “Eureka!” moment is such an old chestnut that it's often dismissed as folklore. But Newton himself always insisted this version of events was true (well, except the part about the apple hitting him on the head). Newton spoke of the incident to many people, including his pen pal Voltaire. In 1726 gave a description to his friend John Conduitt that remains the earliest written record of the event.
“He first thought of his system of gravitation which he hit upon by observing an apple fall from a tree,” Conduitt recounts in the letter, documented by researchers at the University of York. Newton wondered why the apple, or anything else, always fell in the same direction: down.
In fact, what's believed to be the legendary tree still stands at Woolsthorpe Manor, where it had already become famous as early as the 18th century. Over 350 years old, the tree has been re-rooted twice but still stands in the garden of Newton's old home, dropping apples that fall straight to the ground every single time.
By the 1820s, scientists were increasingly intrigued by the phenomena of magnetism and electricity. In the preceding decades Italian physiologist Luigi Galvani had even used a current to move the muscles of animal corpses, an idea that inspired sci-fi books about human reanimation likeMary Shelley’s Frankenstein. But the best minds of the day didn't understand exactly how either worked or believe they were intrinsically linked.
That changed one day, when Danish scientist Hans Christian Oersted was giving a lecture demonstration with an early battery. While setting up his apparatus, he happened to place a compass near the battery and was surprised to see that compass needle moved. The wire carried a current which produced a magnetic field around it, moving the compass alignment to this new field rather than Earth's own magnetic field.
Ever the responsible scientist, Oersted tinkered with reproducing this result for several months. Then he published a pamphlet that shocked the scientific community, showing that electric current actually generates a magnetic field. A decade later, British chemist and physicist Michael Faraday showed that the opposite is also true—a changing magnetic field can produce an electric current.
Electromagnetism, the driving force behind many inventions from the telegraph to the motor, would forever alter the way people lived and worked.
Vulcanized Rubber (1839)
The precursors to rubber left a lot to be desired. Early rubber melted in summer, froze and cracked in winter, and by the 1830s appeared to be an idea whose time had come and gone. Fortunately, a hardware dealer named Charles Goodyear who was convinced that rubber was a miracle product of the future tried to change that.
“His story borders on obsession. In fact, it probably crosses over,” says Gaughan. Goodyear employed many additives, but none did the trick until he accidentally charred some rubber on a hot wood stove. (The most persistent story says a chunk of rubber flew from his hands and landed there while Goodyear was exuberantly defending his product in a general store.)
“The rubber had been mixed with sulfur, and the heating was just what it needed to mix the sulfur in on a molecular level, creating a ‘vulcanized’ rubber that wouldn’t congeal into a sticky mess in the middle of summer. It was such a versatile material that Goodyear published his autobiography in a book made of rubber,” Gaughan says.
Though a prodigious inventor, Goodyear was an abysmal businessman. Although he saw his invention circle the globe, not least on the tires that now bear his name, he failed to profit from it and sadly died in debt.
Synthetic Dye (1856)
In 1856, 18-year-old William Perkin was trying to find a cure for malaria when he stumbled upon a way to color clothes.
Perkin was assisting famed German chemist August Wilhelm von Hofmann, who hoped to find uses for the era's major industrial waste: coal tar, a sludge leftover from the process of turning coal into gaslight. Because it shared chemical similarities with existing medicines like aspirin, Hofmann hoped young Perkin might find a way to use coal tar to cheaply produce quinine, an effective but expensive anti-malarial drug.
Working at home during Easter vacation, Perkin battled against long odds, mixing different coal tar components with potassium dichromate and sulfuric acid. Like a Harry Potter spell gone wrong, instead of quinine, Perkin accidentally produced a purple sludge. Luckily for Perkin, purple in his day was fashion's most coveted color—and the exclusive domain of the wealthy due to the high cost of existing dyes made from crushed snails.
Perkin started a dye factory, democratized the color purple, and launched an entirely new era of chemical industry that made color available to all. Within 50 years more than 2,000 artificial colors were available, with applications ranging from paints to food coloring to medical imaging. Synthetic dyes remain big business and even the name 'coal-tar' dyes has endured, but in reality today most are made from another source—petroleum.
Belgian immigrant Leo Baekeland's first great invention made him a fortune. In 1899, entrepreneur George Eastman bought his photographic printing paper for $750,000—more than $21 million in today's dollars. (Eastman would go on to popularize the camera and found what is today the Kodak Company.) But the chemist's next discovery , Bakelite, proved far more enduring.
In 1907, Baekeland stumbled on a soft synthetic resin that could be shaped and then permanently hardened when put under pressure. “For three years he tried to come up with a flexible material for insulating wires, but ended up making a hard material,” Gaughan says. “Instead of tossing it out as a failure, Baekeland discovered his new material could be shaped into billiard balls, toothbrushes, and airplane propellers."
His discovery was, of course, plastic. The find continues to fuel innovations that are reshaping the future. "Baekeland’s discovery was hailed as the opening of a new era, where humanity could create whatever they wanted, says Gaughan. Today, the era of 3D printing, and the potential to make anything we need anywhere we are, is pushing the limits of what plastics make possible.
The Microwave (1946)
Raytheon engineer Percy Spencer was boosting the power of his company's radar sets when he discovered that a peanut cluster bar in his pocket had melted. “He would always carry a peanut cluster bar in his pocket to break up and feed [squirrels] during lunch,” Percy's grandson George "Rod" Spencer Jr. told Popular Mechanics in 2016. Amazed by the melted squirrel snack, Spencer next tried putting an egg under the magnetron tube—and saw it promptly explode.
“I always thought that was the origin of the expression 'egg in your face,” Rod Spencer said.
The very next day, Percy Spencer invented an enduring staple of microwave cuisine: he brought in kernels of corn and whipped up a batch of popcorn for his coworkers. In fact, one of Spencer's first patent applications touted the potential of microwave pop. Raytheon's first primitive commercial microwave, the “Radarange,” went out for sale the very next year. But it wasn't quite ready for the mainstream—it was the size of a refrigerator and cost some $50,000 in today's dollars.
The “little blue pill” was originally known by the far less catchy name of UK92480. In 1989, Pfizer researchers began researching this compound in the hopes it could be used to treat heart conditions. The idea was to relax blood vessels near the heart to improve circulation. Unfortunately, the pill didn't perform well in clinical trials, but male patients did report a surprising side effect.
Pfizer's Chris Wayman found that Viagra relaxed did relax blood vessels—in the penis, which enabled erections even in men who'd had trouble before. “What was amazing about this study was that we saw a restoration of the erectile response," Wayman told the BBC. "Now we were on to something which could only be described as special.”
"We've always been waiting for the magic bullet," Dr. Fernando Borges of the Florida Impotency Center in St. Petersburg, told Time magazine, just three weeks after the pill hit commerical shelves. "This," he said, "is pretty close to the magic bullet." Viagra didn't turn out to be a cure-all, but it certainly changed the lives of millions of men (and women).