Eureka! 10 accidental discoveries that changed the world

It’s no secret that the best ideas often come to us when we least expect them to. For some it may be on the drive home from work or in the middle of the night, while others may have their lightbulb moments while taking ‘time out’ in the bathroom.

The Ancient Greek mathematician Archimedes was in the latter group, having famously realised how to measure the volume of irregular objects while taking a bath. When he climbed in, the water level rose, and it occurred to him that the volume of water displaced must be equal to his own. How he maintained his reputation after running naked through the streets screaming ‘Eureka’, we’re not sure!

It’s not just ideas that can come to us by chance; sometimes it’s a physical invention. While it’s true that most of history’s greatest discoveries were made after years of painstaking research, others happened completely by accident. Take the humble ice lolly, for example. Arguably a lifesaving invention during the hot summer months, it was initially the result of a failed attempt at making soda. In 1905, an 11-year-old boy called Frank Epperson had been trying to make himself a sugary beverage, but left his concoction outside overnight with the stirrer still in the cup. Being the middle of winter, the liquid froze, and in the morning Frank enjoyed a frozen treat on a stick. Eighteen years later, he realised the commercial possibilities his accidental invention could have, and he began selling them on California beaches.

So whether it’s the result of a clumsy spill or a contaminated laboratory, accidental inventions are just a slapdash scientist away, as long as they are able to realise the potential. Naked celebrations are, of course, optional.

1. The mouldy mistake that created Penicillin

A contaminated experiment is any scientist’s worst nightmare, but in the case of biologist Alexander Fleming, it would be his making. While studying the influenza virus, he accidentally left a petri dish out of the incubator while he was away on holiday. Upon returning, he discovered that the petri dish, in which he had been growing staphylococcus bacteria, had also begun to grow mould. When Fleming examined the dishes more closely he noticed that there was a ring around the mould where the bacteria had not grown. The ‘mould juice’ was actually penicillin, produced by the Penicillium mould that had contaminated the dish. Fleming later found that it was able to kill many different types of bacteria. It was two other scientists, Howard Florey and Ernst Chain, who turned penicillin into a drug, but without Fleming, antibiotics may never have been invented.

Discoverer case file: Sir Alexander Fleming
Born in Scotland in 1881, Fleming went on to study at St Mary’s Hospital, London, where he completed a bachelor’s degree in medicine. His accidental discovery of penicillin earned him a Nobel Prize, which he shared with Florey and Chain.


Click to enlarge the image and discover how modern antibiotics work


2. The botch that led to bakelite… and modern plastics

Throughout the 19th century, scientists tried desperately to solve the mystery of polymers – very large molecules that can be expanded and moulded. In 1870 an American inventor modified a naturally occurring polymer called cellulose to create an incredible new material called celluloid, which could be moulded or rolled when heated. But it would be another 40 years before the first wholly synthetic plastic was made. The discoverer, Leo Baekeland, had been experimenting with synthetic resins. After heating the liquid, he found that it produced a solidified matter, which was insoluble in solvents and did not soften when heated. He called it ‘Bakelite’, and it was soon used in the production of everything from electricals to jewellery.

Discoverer case file: Leo Baekeland
A Belgian chemist born in 1863, Baekeland left his homeland for New York aged 23. Here he invented Velox photographic paper, which allowed developments under artificial light, before turning to plastics.


Bakelite was used to make telephone casings because it was electrically nonconductive and heat-resistant


3. Melted chocolate inspires the microwave

Not only was the microwave discovered by accident, it was also discovered by a man who had not even completed high school. At the age of 12, Percy Spencer left education to work in a spool mill and was later hired to install electricity in a nearby paper mill. In the 1920s, Spencer began working as an engineer for Raytheon, a company that went on to improve radar technology for Allied forces in World War II. One day, he was stood in front of an active radar magnetron when he noticed the chocolate bar in his pocket had melted. He began testing the effects of magnetrons on other foods, and invented the first true microwave oven by attaching a high-density electromagnetic field generator to an enclosed metal box. The oven was a success, and in 1945 the company filed a patent for the first commercial microwave.

Discoverer case file: Percy Spencer
Born in 1893, at eighteen months old Spencer’s father died and his mother left him in the care of his aunt and uncle. Despite his difficult start, he would become one of the world’s most famed physicists


Click to learn how your microwave heats food


4. Persevering with preservatives creates artificial sweeteners

The first artificial sweetener, saccharin, was discovered by a Russian chemist called Constantin Fahlberg. He had been experimenting with preservatives in his work, and while eating a bread roll, he noticed that it had been sweetened by the substance left on his hands. He went back to the lab and retraced his steps, until he was able to synthesise the sweetener in bulk.

Discoverer case file: Constantin Fahlberg
Fahlberg was initially hired to analyse the purity of sugar.

5. Scientist sets his sights high and creates superglue by mistake

This super-sticky substance was discovered by accident – twice! Chemist Harry Coover had been attempting to make clear plastic gun sights for the Second World War, and one formulation he tested produced an extremely quick bonding adhesive. It was useless for his gun sights, though, and he forgot about it until almost ten years later, when he stumbled across it again while developing heat-resistant canopies for jet airplanes. This time he realised its potential, and the product was put on the market.

Discoverer case file: Harry Coover
Coover worked as a chemist for Eastman Kodak.


Great for sticking, useless for gun sights

6. Coca-Cola – the alternative to morphine…

After being wounded in the American Civil War, pharmacist John Pemberton became addicted to morphine. Seeking an alternative, in 1886 he began experimenting with coca – the plant from which cocaine is derived. He eventually stirred up a fragrant, caramel-coloured liquid that he combined with carbonated water and put on sale for five cents a glass. The soda, named Coca-Cola, would become the world’s fourth most valuable brand.
Discoverer case file: John Pemberton
Pemberton established a wholesale drug business.

7. Stainless steel rescued from the scrap pile

Steel has been forged for millennia, but it wasn’t until 1913 that a metallurgist called Harry Brearley discovered a way to stop it rusting. He had been tasked with finding an erosion-resistant metal to prolong the life of gun barrels. Legend has it that as attempt after attempt failed, his pile of scrap metal grew bigger, and he later noticed that one of the scraps hadn’t rusted like the others. He had invented stainless steel, and quickly saw its potential in the cutlery industry.

Discoverer case file: Harry Brearley
Brearley was lead researcher at Brown Firth in 1908.

8. A wrong resistor, and the pacemaker is born

Pacemakers have existed in a very rudimentary form since the 19th century, when it was discovered that electrical impulses could be used to provoke a heartbeat. However, the devices that followed were large and bulky and had to be plugged into a mains current, putting the patient at risk of electrocution. It wasn’t until 1960 that battery-powered implantable pacemakers came into use, having been invented four years previously. Electrical engineer Wilson Greatbatch was working on a heart-rhythm recorder when he added the wrong size of resistor to the circuitry. Rather than recording, he found that the device produced electrical pulses instead. He quickly realised that it could be used to regulate the electrical activity of the heart and guarantee a steady rhythm. Over the next two years, he succeeded in miniaturising the device and making it safe from bodily fluids. The first patient, a 77-year-old man, went on to live for a further 18 months.


Click to find out how a pacemaker helps a human heart beat


Discoverer case file: Wilson Greatbatch

The American engineer and inventor was born in New York in 1919, and served in World War II before completing a degree in electrical engineering. By the time of his death in 2011, he held over 325 patents.


9. Scientist’s slip-up creates slipperiest substance on Earth, Teflon

The non-stick substance found on frying pans was inadvertently invented by a man called Dr Roy Plunkett. He had been trying to synthesise a non-toxic alternative to refrigerants like sulphur dioxide and ammonia, and was experimenting with tetrafluoroethylene (TFE). After storing the gas in cylinders, he opened one to discover that it had polymerised into a waxy white powder that was extremely sticky and had a very high melting point. Three years later, the substance, which was named Teflon, was patented.

Discoverer case file: Roy Plunkett
Plunkett received the John Scott Medal for the “comfort of humankind”.



Click to find out how teflon protects a pan

10. The extra-ordinary error that uncovered X-rays

It was while German physicist Wilhelm Röentgen was investigating the effects of cathode ray tubes that he made a curious discovery. During an 1895 experiment, he evacuated the tube of all air and filled it with gas before passing an electric current through it. Despite it being covered with black paper, he noticed that a screen several feet away was illuminated by the invisible rays, which he named ‘X’ to indicate the unknown. They were later found to pass through human tissue, allowing for the imaging of bones.

Discoverer case file: Wilhelm Röentgen
Born the only child of a cloth merchant in 1845, Röentgen studied mechanical engineering.

First x-ray of human hand taken by W C Rontgen, December 22, 1895

Roentgen took this radiograph of his wife’s left hand

Also read:

Six of the weirdest scientific theories from history

25 mind-blowing facts about gravity

The science of magic tricks