Inventors and innovators change the world around them with each new discovery that they make. Usually, these inventions are the result of many painstaking hours of research, experimentation, and hard work. Once in a while, however, people are working on something completely different when they first stumble upon a discovery. Here is a list of 10 things that were invented by accident!

1. The Microwave Oven (1946, USA, Percy Spencer)

Spencer was building some radar equipment for a radiation laboratory when he noticed that a chocolate bar nearby had completely melted. The first microwave oven was six feet tall and around 750 pounds and the first food ever cooked in a microwave was popcorn!

2. Potato Chips (1853, USA, George Crum)

Crum, a chef at a lodge in New York, had one particularly demanding customer. The customer thought that his fried potatoes were too soggy, so he kept sending them back to be fixed. Crum was getting frustrated, so he sliced the potatoes extremely thin and fried them until they were hard. He was then surprised when the customer asked for more!

3. Post-It Notes (1968, USA, Dr. Spencer Silver and Art Fry)

Dr. Silver, a scientist who worked for 3M, was trying to develop a super-strong adhesive, but instead ended up with a reusable, pressure-sensitive adhesive. Fry, one of his colleagues, thought that it would be a good idea to use it to mark a page like a bookmark, so Silver applied it to some paper and the Post-It was born!

4. X-Rays (1895, Germany, Wilhelm Röntgen)

ntgen was studying cathode ray tubes, which contain beams of electrons. When he was shining light through the tube he noticed that fluorescent papers in his lab were glowing, even though the machine had an opaque outer covering that light could not pass through on its own. Various professors and scientists across the world contributed to the development of an x-ray machine that could be used on humans.

5. Chocolate Chip Cookies (1938, USA, Ruth Graves Wakefield)

Wakefield owned the Toll House Inn, a restaurant in Massachusetts, where she served her own recipes. One day she was making chocolate cookies and ran out of baking chocolate, so she used pieces of sweetened chocolate, thinking that the chocolate would melt into the rest of the batter. It didn't work as she had expected, but the idea of chocolate chip cookies quickly spread and they soon became one of the most popular cookies in the United States!

6. Velcro (1955, Switzerland, George de Mestral)

Engineer George de Mestral was hiking with his dog when he noticed some burrs, which had many tiny hooks, sticking to his clothes and to his dog's fur. He began thinking about practical applications of this and, eventually, he created Velcro. The name came from a combination of the words "velvet" and "crochet" and at first the invention was not well-received. Then NASA began using it and its popularity rapidly grew!

7. Anesthesia (1846, USA, Dr. William Morton)

Nitrous oxide, also known as laughing gas, was originally used for recreational purposes. Dr. Morton thought about this and noticed that there were some anesthetic effects of the drug. He first used it on a patient, Gilbert Abbot, who was getting a tumor removed from his jaw. Abbot was awake during the procedure, but he did not feel any pain. Much more research and development led to modern anesthesia, which is thankfully much safer and more reliable than in 1846!

8. The Implantable Pacemaker (1960, USA, Wilson Greatbatch)

Greatbatch was an electrical engineering professor at the University of Buffalo and he was working on a machine to record a heart beat. He accidentally added the wrong electrical component, causing the machine to produce electric pulses instead of recording them. He soon realized that this could be used to stimulate a heart to beat and the first pacemaker was implanted in a 77-year-old man who lived on for 18 more months!

9. Synthetic Dye (1856, England, William Perkin)

18-year-old chemist William Perkin had a hypothesis about making a natural substance that could treat malaria. One of his experiments was going wrong, but he noticed that the solution had a very bright purple color and realized that it could be used for dye in paint and clothing. He called it mauveine and eventually it was put on the market for commercial purposes!

10. Fireworks (1st Century, China, Unknown)

Sometime, about 2,000 years ago, a Chinese chef accidentally mixed charcoal and sulfur with saltpeter, an ingredient in gunpowder that was also used as a flavoring salt. Burning the mixture on an open flame made the flame change color, but if the mixture of powders was packed into a bamboo tube, it would explode. After many experiments, people learned how to control the explosives to create the fireworks displays that we see today!