Some of the Greatest Inventors Are Women

Martha Coston invented pyrotechnic signal flares:
Martha Coston of Philadelphia was only 21 in 1847 when her husband, Benjamin, an inventor for the Navy, unexpectedly died of pneumonia. Alone, it was up to Coston to support herself and her four small children.

Her invention efforts began when she found a notebook with her husband's ideas for signal flares. He thought they could be used to communicate ship-to-ship or ship-to-land. But when she tested the models he had created they didn't work. At first she worked unsuccessfully with several chemists. Then while watching a fireworks show, she realized that the signals might be able to work using the technology of fireworks. So she sought the advice of experts in that field.

Bingo! In 1859, just before the Civil War, she patented a system of red, white, and green "Pyrotechnic Night Signals." The U.S. Navy bought the rights to the signals for $20,000 and awarded her the contract to manufacture them. During the war, when ships were in trouble or in heavy fog, they set off one of her signals. So did people who were shipwrecked. Coston gained a second U.S. patent in 1871, and also patented her signals in England, France, Holland, Denmark, Italy and Sweden. She sold the signals to navies, shippers and yacht clubs.

She is credited with saving the lives of many, many people all over the world.

Sally Fox invented spinnable colored cotton:
In 1982, entomologist Sally Fox developed the first commercially spinnable colored cotton. She founded FoxFibre to sell her natural cotton for use in clothes and linens.

Stephanie Kwolek invented Kevlar:
In 1971, while working as a chemist at Dupont, Stephanie Kwolek, invented Kevlar, a thread that is five times stronger than the same weight of steel, and is now used to make radial tires, airplanes, boat shells, protective gear for the military, and bulletproof vests. She was inducted into the National Inventors Hall of Fame in 1995.

Rose Totino invented frozen pizza:
Rose Totino, daughter of Italian immigrants who settled in Minneapolis, opened a take out pizza restaurant in the 1950s at a time when almost no one in the U.S. outside of New York or Los Angeles, had ever heard of pizza. It was a big success. After she invented a way to freeze pizza crust so that her customers could bake at home, she a company to sell it, patented her idea in 1979, and Totino's Pizza became the top selling frozen pizza nationwide. She eventually sold her business to the Pillsbury Company in 1975 for $20 million.

Lydia O'Leary invented makeup foundation:
Lydia O'Leary's career choices were limited by the fact that a port wine birthmark covered half her face. So she created a makeup foundation that would cover it. In 1932, she became the first person to receive a patent for a makeup foundation. She founded the Covermark Corporation, now an international company. Her foundation continues to benefit people with birthmarks, scars and other facial blemishes.

Marion Donovan invented the disposable diaper:
In 1946, Marion Donovan sold her invention of the disposable diaper for about $1 million "in order to devote more time to developing other inventions."

Gertrude Elion invented drugs to fight childhood leukemia:
In 1991, when Gertrude Elion was the first woman inducted into the National Inventors Hall of Fame in recognition of her patents for drugs to fight childhood leukemia and ones that facilitated kidney transplants, she said, "I'm the first but I'm sure I won't be the last." And she wasn't. She also received the Nobel Prize in Medicine in 1988.

Elizabeth Hazen and Rachel Brown both invented Nystatin:
Elizabeth Hazen and Rachel Brown invented Nystatin, which was introduced in 1954 as world's first useful antifungal antibiotic. They donated all Nystatin royalties-more than $13 million by the time the patent expired-to academic science through the nonprofit Research Corporation.

Susan Casey is author of Women Invent! Two Centuries of Discoveries That Have Shaped Our World (Chicago Review Press) and Kids Inventing: A Handbook for Young Inventors (Jossey-Bass/Wiley).

Related: The Most Influential Women in Technology