In September 1928, a Scottish scientist came back to his laboratory in London after a summer holiday. His name was Alexander Fleming, and he was not a very tidy man. Before the holiday, he left a pile of glass dishes on his table. Inside them, he was growing bacteria – tiny living things that can make people very ill.
When he looked at the dishes again, he saw something strange. A blue-green mould – the soft, furry stuff that grows on old bread – had appeared in one of them. Around the mould, the bacteria were dead. Fleming did not plan this. He did not even want it. But this small accident gave the world its first antibiotic, a medicine that kills bacteria. It has saved millions of lives since then.
History is full of stories like this. Some of the most important things in our homes and hospitals were not planned at all. In this article, we will look at six of these “happy mistakes” and ask an interesting question: was it really just luck?
A Dirty Dish That Saved Millions
Fleming worked at St Mary’s Hospital in London. He was studying a type of bacteria called Staphylococcus, which causes dangerous infections. In those days, even a small cut could kill you if bacteria got inside it.
Nobody knows exactly where Fleming’s mould came from. Many historians think it flew in through the air, possibly from another laboratory on the floor below. Some researchers also think the weather helped: that summer was cool at first and then warm, which was good for the mould and bad for the bacteria.
Fleming noticed the dead bacteria, and he was curious. He grew more of the mould and tested it. He found that it could kill many different kinds of bacteria. In 1929, he wrote about it in a scientific paper and gave the new substance a name: penicillin, from the name of the mould, Penicillium.
But then something surprising happened – almost nothing. Penicillin was very difficult to produce, and it did not stay stable for long. For about ten years, Fleming’s discovery waited quietly in a scientific journal.
Why a Great Discovery Can Wait Ten Years
The story continued at the University of Oxford. Around 1939, a team led by Howard Florey and Ernst Chain read Fleming’s old paper and decided to try again. By 1941, they had shown that penicillin could cure people with deadly infections. However, they could make only tiny amounts. At first, they grew the mould in hospital bedpans, and they even collected penicillin from patients’ urine so they could use it again.
The Second World War was happening, and soldiers were dying from infected wounds. Britain could not produce enough penicillin, so in July 1941 Florey travelled to the United States for help. He went to a government laboratory in Peoria, a small city in Illinois. Scientists there started to grow the mould in huge tanks.
Then came a second lucky accident. A laboratory worker in Peoria, Mary Hunt, found a mouldy melon at a local market. Its golden mould produced much more penicillin than Fleming’s original mould.
The result was amazing. Before the D-Day landings in France in June 1944, factories produced about 2.3 million doses of penicillin for the soldiers. In 1945, Fleming, Florey and Chain shared the Nobel Prize in Medicine.
The Chocolate Bar in an Engineer’s Pocket
Our next story also starts during the Second World War. Percy Spencer was an engineer at an American company called Raytheon. His family was poor, and he left school at the age of 12. But he taught himself physics and mathematics, and he became one of the world’s best experts on radar.
One day in 1945, Spencer was standing next to a working magnetron – the part of a radar machine that produces microwaves. He put his hand in his pocket and found that his chocolate bar had melted. But Spencer was the one who asked “Why?” and did an experiment.
He put some corn kernels near the magnetron, and they turned into popcorn. According to a popular story, he also tried an egg. It got so hot that it exploded – some say in the face of a colleague who came too close.
Raytheon asked for a patent for a microwave oven on 8 October 1945. The first one went on sale in 1947, and it was very different from the small box in your kitchen. It was almost 1.8 metres tall, weighed about 340 kilograms and cost about 5,000 dollars. In 1967, a smaller kitchen model appeared for 495 dollars, and slowly microwaves became normal in homes.
And what did Spencer get for his invention? The company gave him a bonus of just two dollars – its usual payment for a patent. But he had a long career there and collected about 300 patents in his life.
A Strange Light in a Dark Room
Let’s go back further in time, to the evening of 8 November 1895. In the German city of Würzburg, a physics professor called Wilhelm Röntgen was doing experiments with a special glass tube. He was sending electricity through it. He covered the tube with black cardboard, so no light could come out, and he turned off the lights in the room.
Then he saw something impossible. A small screen on a table, about a metre away, began to glow. Something invisible was coming out of the tube, going through the cardboard and hitting the screen. Röntgen did not know what it was, so he gave it a mathematical name for an unknown thing: X-rays.
He discovered that X-rays could pass through paper, wood and even skin – but not through bones or metal. On 22 December 1895, he asked his wife, Anna Bertha, to put her hand in front of the rays. The picture showed the bones of her hand and her wedding ring. When she saw it, she reportedly said, “I have seen my death.”
The news travelled around the world very quickly. Within a few months, doctors were using X-rays to find broken bones and bullets inside people’s bodies. In 1901, Röntgen received the very first Nobel Prize in Physics. Interestingly, he decided not to patent his discovery. He wanted everyone to be able to use it freely.
One Glue Too Weak, One Glue Too Strong
Sometimes a mistake is not useful at first. It needs the right person and the right problem. Two famous glues show this very well.
In 1968, Spencer Silver, a scientist at the American company 3M, was trying to make a very strong glue for planes. Instead, he made a very weak one. It could stick paper to a surface, but you could easily pull the paper off and stick it again somewhere else. Silver called it “a solution waiting for a problem.”
The problem appeared six years later, in a church. Art Fry, another 3M worker, sang in a church choir. He used small pieces of paper as bookmarks in his song book, but they kept falling out. Then he remembered Silver’s weak glue. A bookmark with this glue would stay on the page but would not damage it. Fry soon realised that sticky paper was even better for short notes. Then, the product went on sale across the United States in 1980 with a new name: the Post-it Note. It took twelve years to get from the mistake to the shop.
The opposite story happened in 1942. Harry Coover, a chemist at the company Eastman Kodak, was trying to make clear plastic for gun sights during the war. One of his materials was terrible for this job, because it stuck to everything it touched. He threw the idea away. Nine years later, in 1951, Coover met the same material again during another project. This time, he understood that “sticks to everything” was not a problem – it was the product. The glue went on sale in 1958, and later it became known as Super Glue.
A Walk, a Dog and Thousands of Tiny Hooks
Not every accident happens in a laboratory. In 1941, a Swiss engineer called George de Mestral went for a walk in the mountains with his dog. When they came home, both his trousers and the dog’s fur were covered in burrs – small, round seeds from a plant that stick to everything.
De Mestral looked at them under a microscope. He saw that each burr had hundreds of tiny hooks. These hooks caught on the small loops in cloth and in animal fur. He thought: what if people could make the same system from fabric?
He worked on the idea for about ten years, and many experts laughed at it. In the end, he found that nylon was the right material for the hooks. He received a patent in 1955 and named his invention Velcro, from two French words: velours (a soft cloth) and crochet (hook). Today, Velcro is on shoes, bags and jackets – and astronauts have used it to stop things floating around inside their spacecraft.
Is It Really Just Luck?
These stories have something in common. In each one, there was an accident. But in each one, there was also a person who noticed it and asked a question. A melted chocolate bar or a dirty dish is not an invention. It only becomes one when someone is curious, patient and knows enough to understand what they are seeing.
The French scientist Louis Pasteur explained this idea in a speech in 1854:
“In the fields of observation, chance favours only the prepared mind.” – Louis Pasteur
English even has a special word for a happy discovery that you were not looking for: serendipity. The writer Horace Walpole invented it in a letter in 1754. He took it from an old story called “The Three Princes of Serendip.” Serendip was an old name for Sri Lanka, and the princes in the story kept discovering things by accident and by being clever.
We should also be careful, because some famous “accident” stories are not true. For example, many websites say that a cook named George Crum invented potato chips in 1853, when an angry customer complained that his fries were too thick. Historians are not sure this ever happened. In fact, a recipe for very thin fried potato slices appeared in an English cookbook in 1817, many years earlier.
Conclusion: What Will Your Next Mistake Be?
Penicillin, the microwave oven, X-rays, Post-it Notes, Super Glue and Velcro all started as surprises. But none of them was pure luck. Fleming needed ten years and a team at Oxford. Silver needed Fry and his song book. Coover needed to see his “failure” twice before he understood it.
Maybe the real lesson is not “mistakes are good.” Most mistakes are just mistakes. The lesson is that something unexpected is a question, not only a problem. The next time something goes wrong in your kitchen, at work or in your studies, try to stop for a moment and ask what Spencer asked about his chocolate: “Why did that happen?” Perhaps the answer will be small. Or perhaps, like a mouldy dish in 1928, it will change the world.
