10 Important Science Discoveries That Were Complete Accidents


Photo: AP

Many of the great discoveries of our past have been found through pure accident.The reasons for these accidental discoveries range from clumsiness and luck to unclean or unsafe laboratory practices.

The microwave

In 1946 Percy Spencer, an engineer for the Raytheon Corporation, was working on a radar-related project. While he was testing a new vacuum tube that drives a radar set known as a magnetron, he discovered that a chocolate bar he had in his pocket melted.

He became intrigued and started experimenting by aiming the tube at other items, such as eggs and popcorn kernels. He concluded that the heat the objects experienced was from the microwave energy.

The first microwave weighed 750 pounds and stood 5' 6' tall. The first countertop microwave was introduced in 1965 and cost $500.


In 1895 Wilhelm Roentgen, a professor of physics, was working with a cathode ray tube.

Although the tube was covered, he noticed a nearby fluorescent screen would glow when the tube was on. He tried placing items between the object and the screen to block the rays, but found that a number of objects could be penetrated by the rays. When he placed his hand in front he noticed he can see his bones.

He began using film to capture the images, and one of the first set of x-rays was of his wife's hand. The x-rays were being used clinically in the United States by 1896.


In 1896, intrigued by the discovery of x-rays, Henri Becquerel decided to investigate the connection between them and naturally occurring phosphorescence.

In March 1896 Becquerel attempted to expose photographic plates using uranium salts. He thought he needed sunlight to complete his experiment, but the sky was overcast. He stored his items and decided to wait for a sunny day.

To his surprise he discovered the photographic plates were exposed, as if the sun had hit them. The rays were coming from the radioactive uranium salts.

Sweet'N Low

Saccharin, the artificial sweetener in 'Sweet'N Low,' is somewhere around 400 times sweeter than sugar. It was discovered in 1879 by Constantine Fahlberg who was actually working on substitution products of coal tar.

After a long day in the lab, he forgot to wash his hands before eating dinner. When the bread and everything he touched tasted sweet, he remembered he spilled a chemical on his hands earlier.

Fahlberg patented saccharin in 1884 and began mass production. The artificial sweetener became widespread when sugar was rationed during World War I. In 1907 diabetics started using the sweetner as a replacement for sugar and it was soon labelled as a noncaloric sweetener (for dieters) because the body can't break it down, so we don't get any calories.

The pacemaker

In 1956 Wilson Greatbath was building a heart rhythm recording device. He reached into a box for a resistor to complete the circuitry, but pulled out the wrong size.

When he installed the ill-fitting resistor, the circuit emitted electrical pulses, which he matched up to the timing and rhythm of the heart's electrical activity. He thought this rhythmic electrical stimulation could compensate for a breakdown in the heart's ability to pump its own muscles.

He began to shrink his device and on May 7, 1958 a version of his pacemaker, just two cubic inches wide, was successfully inserted into a dog.


Albert Hofmann was studying Lysergic acid, a powerful chemical that was first isolated from a fungus that grows on rye, when he first synthesized LSD in 1943.

These chemicals were being studied to be used as pharmaceuticals, and many derivatives of them are still used today.

While working with this chemical, sometime about five years after it was synthesized, Hoffmann reported feeling restless and dizzy. He went home to lay down and 'sank into a kind of drunkenness which was not unpleasant and which was characterised by extreme activity of the imagination.'

He intentionally dosed himself with the drug on April 19, 1943 to find out its effects.


In 1928 Alexander Fleming, a professor of bacteriology, returned to his lab after a vacation. While sorting through his petri dishes of colonies of the bacteria Staphylococcus, he noticed mould started to grow on them.

Looking for what colonies he could salvage from those infected with the mould, he noticed that the bacteria wasn't able to grow around the mould. The mould actually turned out to be a rare strain of Penicillium notatum that secreted a substance that inhibited bacterial growth.

Penicillin was introduced in the 1940's, opening up the era of antibiotics.


Viagra was the first treatment for erectile dysfunction, but that is not what it was originally approved for.

Pfizer originally introduced the chemical slatternly, the active drug in Viagra, as a heart medication. During clinical trials, the drug proved ineffective for heart conditions, but surprisingly men noted when they were on the drug they had stronger and longer lasting erections.

Some men that had been impotent were once again fully functional when they were on the drug.

Pfizer went ahead with clinical trials on 4,000 men with erectile dysfunction, and saw the same results. Enter, the age of Viagra.


Alfred Nobel accidentally discovered dynamite in 1833.

Nitroglycerin was becoming a widely produced explosive, even thought it was unstable and regularly blew up people and buildings. While working with nitroglycerin one afternoon, a vial slipped out of Nobel's hand. Luckily, there was no explosion. The nitroglycerin landed in sawdust, and was soaked up.

He was later able to explode the sawdust, and conclude that mixing the nitroglycerin with an inert substance could make it more stable.

Safety glass

In 1903 Edouard Benedictus, a French scientist, dropped glass flask and it did not shatter.

The pieces of glass were broken, but they stayed in place and maintained the shape of the container. Upon investigation Benedictus found that the flask had originally contained a solution of cellulose nitrate, a liquid plastic that had evaporated.

This was the first type of safety glass developed, a product which is now frequently used in car windshields, safety goggles, and much more.

Now for some more mind blowing inventions.

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