Top 5 accidental inventions & discoveries

What do microwaves, penicillin, and one of America's favorite snack foods have in common? “Not much,” you may be thinking, but in fact, each one began by accident. From post-it notes to superglue, here's the lowdown on the top five accidental inventions and discoveries.

5. Post-it notes

The invention of Post-it notes, a favorite office supply of cubicle dwellers all over the world, was a fluke. In 1970, Spencer Silver's job was to discover a stronger adhesive for his employer, 3M.

He succeeded in creating a new adhesive, but it wasn't stronger, it was weaker. So while the adhesive did its job in sticking things like paper together, it wasn't so sticky as to tear the paper if it was pulled apart.

Not knowing what to do with this discovery, he set it aside until one day, a friend of his used the adhesive to coat several bookmarks so they wouldn't fall out from between the pages. Ten years later, the adhesive made its debut as the Post-it note, and the rest is history.

4. Microwave oven

Today microwave ovens are a commonplace household appliance for cooking or reheating food, but this was not always the case. When microwaves were first invented, no one thought they could be used to cook food.

In 1945 Percy Lebaron Spencer, an engineer at Raytheon, was working with magnetrons. These devices emitted microwaves--radio signals used in early radar systems. One day Spencer noticed that a candy bar in his pocket had melted. It wasn't long before he realized that the microwaves emitted from the magnetron actually cooked his candy bar.

That year Raytheon filed a patent for the microwave cooking process, and the microwave oven for household use was introduced to the American public in 1967.

3. Krazy Glue and Super Glue

Super Glue is a synthetic glue made from cyanoacrylate, a substance discovered in 1942 by Dr. Harry Coover, a scientist at Kodak Research Laboratories. Coover, whose focus was on developing plastic lenses for gun sights, thought the substance was too sticky to be of any use for his work and rejected it. It was not until 1958 that it was “rediscovered,” patented, and marketed as “Eastman 910.” Today it is sold under the trade names Krazy Glue and Super Glue.

2. Potato chips

Potato chips, a variation on the french fry, were created by George Crum, who, in 1853, was working as a chef at a resort in Saratoga Springs, NY. While being served his potato fries, one patron complained that the slices were too thick. To spite him, Crum created paper-thin and very crispy potato slices that were impossible to eat with a fork, as was the proper etiquette at the time. The plan backfired when the customer was delighted with the crisp chips, and the Saratoga Chip was born. Those Saratoga Chips have become today's ubiquitous potato chips.

1. Penicillin

The most famous and important accidental discovery is the modern miracle medicine, penicillin. In 1928, Alexander Fleming, a Scottish scientist working in a London hospital laboratory, was studying staphylococcus, the bacteria that cause staph infections.

Before setting off on vacation, he added some of the bacteria to several petri dishes, expecting it to grow while he was gone. Instead, something else happened. Upon his return, he noticed a mold growing in some of the petri dishes, but little to no growth of the staph bacteria. Upon further analysis, he discovered that the mold secreted a byproduct that inhibited the growth of the staphylococcus bacteria. He called it penicillin, and the first antibiotic in the world was discovered—entirely by accident.