Stephanie Kwolek was an American chemist who discovered the lightweight, but stronger-than-steel material Kevlar. She was working at the chemical company DuPont and in 1964, her group began searching for a strong, but lightweight fiber that could replace steel used in tires. Unexpectedly, while working in the laboratory, Kwolek got a fluid, turbid, and buttermilk-like in appearance polymer solution, while usually its viscosity would be reminiscent of molasses and it would be translucent. The scientist convinced her colleague to test her solution and they discovered the new fiber that was stronger than steel—Kevlar. Now it is used as a material in more than 200 applications, including tires, for which it was intended, but also parachute lines, boats, airplanes, ropes, cables, bullet-proof vests, etc.