Top 10 Eureka Moments

Most inventions and scientific advances really come after hours and hours of hard work in the lab and years of trying to wring funding from a stone.

But these stories represent times when inspiration struck like a bolt out of the blue and the world was changed by that eureka… that, or these scientists are just the ones with the best P.R.

Archimedes is the man who made eureka famous; of course he's on the list.

1: Special Relativity

It was only very recently that psychologists discovered the science behind eureka, or aha moments.

That eureka moment involves first being stuck and then relaxing your mind. That's exactly how special relativity came to Einstein. For years he had been trying to reconcile - or prove one of - two seemingly contradictory theories about space and time.

While riding a street car home one day, he was struck by the sight of Bern's famous clock tower. The answer was simple and elegant: time can beat at different rates throughout the universe, depending on how fast you moved.

2: Alternating Current

Nikola Tesla was one of those strange people for whom eureka moments were the norm. Ideas for inventions would spring from his head, fully formed, like Athena.

One of his most famous eurekas, though, was the idea for alternating current. From the first time he saw direct current demonstrated, Tesla knew that there had to be a better way, but the answer eluded him.

One day he was out for a walk (quoting Faust, according to legend) when it just came to him. He used his walking stick to draw a picture explaining how alternating current would work to his walking partner.

Tesla partnered with George Westinghouse to advocate for Alternating Current, or AC, over Thomas Edison's DC, or Direct Current. AC eventually was adopted, but not before a publicity battle so bitter that it would put many of today's political campaigns to shame.

3: Nerve Impulses Transmitted Chemically

Otto Loewi discovered that nerve impulses were transmitted chemically, not electronically, all thanks to a dream.

In the early 1900's scientists first proposed the idea of chemical transmission of nerve impulses, but 15 years later it was still just that - a hypothesis. Otto Loewi was about to change all that.

The story goes that just before Easter Sunday, in 1920, Loewi dreamed of an experiment he could do that would prove once and for all how nerve impulses were transmitted. He woke up in the middle of the night, excited and happy, scribbled the experiment down and went back to sleep.

When he woke up, he couldn't read his notes. Luckily, he had the same dream the next night. The experiment and his later work earned him the title, the "Father of Neuroscience."

4: Archimedes and the Golden Crown

He may not have been the first person in history to get a sudden flash of inspiration, but Archimedes is the man who made eureka famous.

It all started when King Hiero II was skeptical about his new laurel leaf-shaped crown. The king wanted to know whether the crown was solid gold, or if some other metal had been added.

It was up to Archimedes to figure this out. Only there was one catch: he couldn't destroy the crown.

After what probably felt like days with the Jeopardy theme song playing in his head ad nauseum, Archimedes drew a bath and suddenly it all became clear. He could determine the density of the crown by noting how much water it displaced. If any other material had been added to the crown, it would be less dense than if it were made entirely of gold.

Archimedes was so excited that he ran naked through the streets (remember, he was about to take a bath) shouting, "Eureka! I have found it!"

5: Television

Philo Farnsworth is kinda the Abraham Lincoln of inventors - he was born in a log cabin, had quite a hike to school (there might have even been snow!) and he fought an historic fight - more on the fight in a bit; eureka moment first.

The 14-year-old Farnsworth was plowing a potato field one day when it suddenly just came to him how electrical television could work. No, there weren't hallucinogens in the spuds. According to legend, the back-and-forth motion of the till inspired him. Farnsworth realized that an electron beam could scan images line by line - simply put, that was the basis for almost all TVs until LCD and plasma screens came along.

He went on to demonstrate the first operational, all-electronic television system in 1927.

Almost immediately he was embroiled in a legal battle with RCA, who claimed that their scientists had come up with - and patented the idea - first. The U.S. Patent Office disagreed and sided with Farnsworth, but years of legal battles and media smear campaigns took their toll. Farnsworth died in near obscurity in 1971.

6: PCR

One Friday night in the 1980s Kary Mullis was driving from Berkeley, where he worked, to Mendocino, Calif., where he had a cabin.

The drive is about three hours long, but the brainstorm Mullis had behind the wheel will most likely last forever. Mullis wasn't trying to solve a particular problem during that drive, just thinking out loud when, according to him, he came up with PCR, a process by which a teeny-tiny bit of DNA can be exponentially amplified.

That amplification allows for all kinds of applications - everything from the diagnosis of hereditary diseases to catching criminals and paternity testing.

7: Coordinate Geometry

Forget "I think there for I am." Descartes' real gift to mankind is a great reason to sleep late: an important aha moment.

Descartes liked to stay in bed until around noon. The habit started when he was a sick kid, and he stuck with it for the rest of his life. But don't think that Descartes was wasting time hitting the 17th century equivalent of the snooze button over and over. One day, while watching a fly flit around above his head, Descartes realized he could describe the fly's position by saying how far it was from the walls and ceiling.

Sounds like "well duh" now, because you probably studied coordinate geometry, a.k.a. Cartesian geometry (named after guess who), while you were in school.

8: Microwave Oven

Like your microwave, thank the military. The microwave was born when engineer Percy Spencer was working on magnetrons for some military radar sets.

According to legend, Spencer had a bit of inspiration when a candy bar he had in his pocket melted near the radar he was working on.

Spencer, being a clever engineer and all, knew that the microwaves being emitted by his magnetron could penetrate the exterior of a food and cook it from the inside - unlike using plain old heat from an oven, or fire which cooks food from the outside in.

9: Velcro

We wouldn't blame you if you were pretty sick and tired of hearing about how so many great inventions and scientific advances come from nature, but in the case of Velcro it's really true.

One day George de Mestral took his dog for a walk in the woods. When he and Fido got back, Mestral noticed burrs all over his pants. The tricky little devils would not come off.

Louis Pasteur said, "Chance favors the prepared mind," and boy was Mestral prepared. Looking at the burrs under a microscope, he saw that they had tiny hooks that had attached themselves to the loops of thread in his pants.

No word on whether he was specifically thinking about kids who can't tie their shoes when he brought Velcro to the world, but they are certainly among his most satisfied customers.

10: Post-Its

Spencer Silver spent years trying to get his colleagues at 3M excited about his low-tack, pressure-sensitive adhesive. The world yawned.

But one day another 3M scientist was in church, not a bad place for a eureka moment, and came up with a use for Dr. Silver's glue.

Arthur Fry was annoyed that the bookmarks in his hymnal wouldn't stay put. He thought adding Dr. Silver's adhesive to some paper might do the trick. Not only was he right, but people have been coming up with uses for the Post-Its ever since.