10: Circular Saw
In the late 18th century, a religious sect known as the Shakers emerged. Shakers valued living communally (albeit celibately), equality between the sexes and hard work. Tabitha Babbitt lived in a Shaker community in Massachusetts and worked as a weaver, but in 1810, she came up with a way to lighten the load of her brethren. She observed men cutting wood with a pit saw, which is a two-handled saw that requires two men to pull it back and forth. Though the saw is pulled both ways, it only cuts wood when it's pulled forward; the return stroke is useless. To Babbitt, that was wasted energy, so she created a prototype of the circular saw that would go on to be used in saw mills. She attached a circular blade to her spinning wheel so that every movement of the saw produced results. Because of Shaker precepts, Babbitt didn't apply for a patent for the circular saw she created.
9: Chocolate Chip Cookies
There is no doubt that many treasured recipes came about through accidental invention in the kitchen, but we must single out one of the most enduring -- and delicious -- of these recipes: the chocolate chip cookie.
Ruth Wakefield had worked as a dietitian and food lecturer before buying an old toll house outside of Boston with her husband. Traditionally, toll houses were places weary travelers paid their road tolls, grabbed a quick bite and fed their horses. Wakefield and her husband converted the toll house into an inn with a restaurant. One day in 1930, Wakefield was baking up a batch of Butter Drop Do cookies for her guests. The recipe called for melted chocolate, but Wakefield had run out of baker's chocolate. She took a Nestle chocolate bar, crumbled it into pieces and threw it into her batter, expecting the chocolate pieces to melt during baking. Instead, the chocolate held its shape, and the chocolate chip cookie was born.
Nestle noticed that sales of its chocolate bars jumped in Mrs. Wakefield's corner of Massachusetts, so they met with her about the cookie, which was fast gaining a reputation among travelers. At Wakefield's suggestion, they began scoring their chocolate (cutting lines into the bar that allow for easier breaking) and then, in 1939, they began selling Nestle Toll House Real Semi-Sweet Chocolate Morsels. The Wakefield cookie recipe was printed on the back of the package; in exchange, Ruth Wakefield received free chocolate for life
8: Liquid Paper
Bette Nesmith Graham was not a very good typist. Still, the high school dropout worked her way through the secretarial pool to become the executive secretary for the chairman of the board of the Texas Bank and Trust. It was the 1950s, and the electric typewriter had just been introduced. Secretaries often found themselves retyping entire pages because of one tiny mistake, as the new model's carbon ribbon made it difficult to correct errors.
One day, Graham watched workers painting a holiday display on a bank window. She noticed that when they made mistakes, they simply added another layer of paint to cover them up, and she thought she could apply that idea to her typing blunders. Using her blender, Graham mixed up a water-based tempera paint with dye that matched her company's stationary. She took it to work and, using a fine watercolor brush, she was able to quickly correct her errors. Soon, the other secretaries were clamoring for the product, which Graham continued to produce in her kitchen. Graham was fired from her job for spending so much time distributing what she called "Mistake Out," but in her unemployment she was able to tweak her mixture, rename the product Liquid Paper and receive a patent in 1958. Even though typewriters have been replaced by computers in many offices, many people still have a bottle or two of that white correction fluid on hand.
7: The Compiler and COBOL Computer Language
When we think about advancements in computers, we tend to think about men like Charles Babbage, Alan Turing and Bill Gates. But Admiral Grace Murray Hopper deserves credit for her role in the computer industry. Admiral Hopper joined the military in 1943 and was stationed at Harvard University, where she worked on IBM's Harvard Mark I computer, the first large-scale computer in the United States. She was the third person to program this computer, and she wrote a manual of operations that lit the path for those that followed her. In the 1950s, Admiral Hopper invented the compiler, which translates English commands into computer code. This device meant that programmers could create code more easily and with fewer errors. Hopper's second compiler, the Flow-Matic, was used to program UNIVAC I and II, which were the first computers available commercially. Admiral Hopper also oversaw the development of the Common Business-Oriented Language (COBOL), one of the first computer programming languages. Admiral Hopper received numerous awards for her work, including the honor of having a U.S. warship named after her.
6: Colored Flare System
When Martha Coston was widowed in 1847, she was only 21 years old. She had four children to support, but she hadn't a clue about how to do so. She was flipping through her dead husband's notebooks when she found plans for a flare system that ships could use to communicate at night. Coston requested the system be tested, but it failed.
Coston was undeterred. She spent the next 10 years revising and perfecting her husband's design for a colored flare system. She consulted with scientists and military officers, but she couldn't figure out how to produce flares that were bright and long-lasting while remaining easy to use at the spur of the moment. One night she took her children to see a fireworks display, and that's when she hit upon the idea of applying some pyrotechnic technology to her flare system. The flare system finally worked, and the U.S. Navy bought the rights. The Coston colored flare system was used extensively during the Civil War.
Unfortunately, the flare system wasn't the best way for Coston to support her family. According to military documents, Coston produced 1,200,000 flares for the Navy during the Civil War, which she provided at cost. She was owed $120,000, of which she was only paid $15,000; in her autobiography, Coston attributed the Navy's refusal to pay to the fact that she was a woman [source: Pilato].
5: The Square-bottomed Paper Bag
Margaret Knight didn't invent the paper bag, but those first paper bags weren't all that useful for carrying things. They were more like envelopes, so there was no way they'd become the grocery store staple that they are today. For that, we have to thank Knight. Knight realized that paper bags should have a square bottom; when weight was distributed across the base in this way, the bags could carry more things.
In 1870, she created a wooden machine that would cut, fold and glue the square bottoms to paper bags. While she was working on an iron prototype of the machine to use for her patent application, she discovered that her design had been stolen by a man named Charles Annan, who had seen her wooden machine a few months earlier. She filed a patent interference suit against Annan, who claimed that there was no way that a woman could have developed such a complex machine. Knight used her notes and sketches to prove otherwise, and she was granted the patent for the device in 1871.
That was hardly Knight's first patent, though. At the age of 12, Knight had developed a stop-motion device that would automatically bring industrial machines to a halt if something was caught on them, which prevented many injuries; all told, Knight was awarded more than 20 patents.
4: Dishwasher
You might think that the first dishwasher was invented by someone who spent years washing dishes, bemoaning the wasted time and the dishpan hands. Actually, Josephine Cochrane, who received the patent for the first working dishwasher, didn't spend that much time washing dishes. The real impetus for her invention was frustration over her servants breaking her heirloom china after fancy dinners.
Cochrane was a socialite who loved to entertain, but after her husband died in 1883, she was left with massive debt. Rather than selling off that beloved china, she focused on building a machine that would wash it properly. Her machine relied upon strong water pressure aimed at a wire rack of dishes, and she received a patent for the device in 1886. Cochrane claimed that inventing the machine was nowhere near as hard as promoting it [source: Lienhard]. At first, the Cochrane dishwasher tanked with individual consumers, as many households lacked the hot water heaters necessary to run it, and those that had the capacity balked at paying for something that housewives did for free. Undaunted, Cochrane sought appointments with large hotels and restaurants, selling them on the fact that the dishwasher could do the job they were paying several dozen employees to do. In time, however, more households acquired the device as greater numbers of women entered the workplace.
3: Windshield Wiper
At the dawn of the 20th century, Mary Anderson went to New York City for the first time. She saw a much different New York City than the one tourists see today. There were no cabs honking, nor were there thousands of cars vying for position in afternoon traffic. Cars had not yet captured the American imagination and were quite rare when Anderson took that trip, but the woman from Alabama would end up inventing something that has become standard on every automobile. During her trip, Anderson took a tram through the snow-covered city.
She noticed that the driver had to stop the tram every few minutes to wipe the snow off his front window. At the time, all drivers had to do so; rain and snow were thought to be things drivers had to deal with, even though they resulted in poor visibility. When she returned home, Anderson developed a squeegee on a spindle that was attached to a handle on the inside of the vehicle. When the driver needed to clear the glass, he simply pulled on the handle and the squeegee wiped the precipitation from the windshield. Anderson received the patent for her device in 1903; just 10 years later, thousands of Americans owned a car with her invention
2: Nystatin
Long-distance romantic relationships are often troubled, but Rachel Fuller Brown and Elizabeth Lee Hazen proved that long-distance professional relationships can yield productive results. Both Brown and Hazen worked for the New York State Department of Health in the 1940s, but Hazen was stationed in New York City and Brown was in Albany. Despite the miles, Brown and Hazen collaborated on the first successful fungus-fighting drug.
In New York City, Hazen would test soil samples to see if any of the organisms within would respond to fungi. If there was activity, Hazen would mail the jar of soil to Brown, who would work to extract the agent in the soil that was causing the reaction. Once Brown had found the active ingredient, it went back in the mail to Hazen, who'd check it against the fungi again. If the organism killed the fungi, it would be evaluated for toxicity. Most of the samples proved too toxic for human use, but finally Brown and Hazen happened upon an effective fungus-killing drug in 1950. They named it Nystatin, after New York state. The medication, now sold under a variety of trade names, cures fungal infections that affect the skin, vagina and intestinal system. It's also been used on trees with Dutch elm disease and on artwork affected by mold.
1: Kevlar
It was just supposed to be a temporary job. Stephanie Kwolek took a position at DuPont in 1946 so she could save enough money to go to medical school. In 1964, she was still there, researching how to turn polymers into extra strong synthetic fibers. Kwolek was working with polymers that had rod-like molecules that all lined up in one direction.
Compared to the molecules that formed jumbled bundles, Kwolek thought the uniform lines would make the resulting material stronger, though these polymers were very difficult to dissolve into a solution that could be tested. She finally prepared such a solution with the rod-like molecules, but it looked unlike all the other molecular solutions she'd ever made. Her next step was to run it through the spinneret, a machine that would produce the fibers. However, the spinneret operator almost refused to let Kwolek use the machine, so different was this solution from all the others before; he was convinced it would ruin the spinneret.
Kwolek persisted, and after the spinneret had done its work, Kwolek had a fiber that was ounce-for-ounce as strong as steel. This material was dubbed Kevlar, and it's been used to manufacture skis, radial tires and brake pads, suspension bridge cables, helmets, and hiking and camping gear. Most notably, Kevlar is used to make bulletproof vests, so even though Kwolek didn't make it to medical school, she still saved plenty of lives.
