Katharine Burr Blodgett Biography

Katharine Burr Blodgett, the first woman to become a General Electric (GE) scientist, made several significant contributions to the field of industrial chemistry. The inventor of invisible, or non-reflecting, glass, Blodgett spent nearly all of her professional life working in the Schenectady, New York, GE plant. Although Blodgett's name has little household recognition, some of the techniques in surface chemistry that she and her supervisor and mentor Irving Langmuir developed are still used in laboratories; in addition, Blodgett's invisible glass is used extensively in camera and optical equipment today.

Blodgett was born on January 10, 1898 in Schenectady, New York, the town in which she spent most of her life. Her parents had moved to Schenectady earlier in the decade from their native New England when Blodgett's father, George Bedington Blodgett, became the head of the patent department at the GE plant opening up in town. Blodgett never knew her father, who died a few weeks before she was born. Left widowed with two small children, Blodgett's mother, Katharine Buchanan Burr, decided to move back east to New York City; three years later, she moved the family to France so that her children would be bilingual. After a few years of French schooling, Blodgett spent a year at an American school in Saranac Lake, New York, followed by travel in Germany. While in her mid-teens, Blodgett returned with her family to New York City where she attended the now-defunct Rayson School. Blodgett later won a scholarship to the all-women's Bryn Mawr College, where she excelled at mathematics and physics.

After college, Blodgett decided that a career in scientific research would allow her to further pursue both of these academic interests. During Christmas vacation of her senior year, she traveled to upstate New York to explore employment opportunities at the Schenectady GE plant. Some of George Blodgett's former colleagues in Schenectady introduced his daughter to research chemist Irving Langmuir . After conducting to a tour of his laboratory, Langmuir told eighteen-year-old Blodgett that she would need to broaden her scientific education before coming to work for him.

Taking Langmuir's advice, Blodgett enrolled in the University of Chicago in 1918 to pursue master's degree in science. Since she knew that a job awaited her in industrial research, Blodgett picked a related thesis subject: the chemical structure of gas masks. Upon graduating, Blodgett returned to GE, where Langmuir hired her as his assistant (the first female research scientist the company had ever employed). At the time, Langmuir--who had worked on vacuum pumps and light bulbs early in his GE career--had turned his attention to studying current flow under restricted conditions. Blodgett soon started working with Langmuir on these studies; between 1918 and 1924, the two scientists wrote several papers about their work. Blodgett's collaboration with the 1932 Nobel winner lasted until Langmuir's death in 1957.

Blodgett soon realized that she would need a doctoral degree if she wanted to further her career at GE. Six years after Blodgett started working for him, Langmuir arranged for his associate to pursue doctoral studies in physics at the Cavendish Laboratory at England's Cambridge University. Blodgett needed her mentor's help to gain admission to Cavendish because laboratory administrators hesitated to give one of their few open spots to a woman. With Langmuir's endorsement, however, Blodgett was able to persuade the Cambridge physicists--including Nobel winner Ernest Rutherford --to allow her entrance. In 1926, Blodgett became the first woman to receive a doctorate in physics from Cambridge University.

When Blodgett returned to Schenectady, Langmuir encouraged her to embellish some of his earlier discoveries. First, he set her to work on perfecting tungsten filaments in electric lamps (the work for which he had received a patent in 1916). Langmuir later asked his protege to concentrate her studies on surface chemistry. In his own long-standing research on the subject, Langmuir had discovered that oily substances formed a one-molecule thin film when spread on water. By floating a waxed thread in front of stearic acid molecules, the scientist showed that this layer was created by the molecules' active ends resting on the water's surface. Blodgett decided to see what would happen if she dipped a metal plate into the molecules; attracted to the metal, a layer of molecules formed similar to that on the water. As she inserted the plate into the solution again and again, Blodgett noticed that additional layers--all one molecule--formed on top of one another. As the layers formed, different colors appeared on the surface, colors which could be used to gauge how many layers thick the coating was. Because this measurement was always constant, Blodgett realized she could use the plate as a primitive gauge for measuring the thickness of film within one micro-inch.

Not long after Blodgett's discovery, GE started marketing a more sophisticated version of her color gauge for use in scientific laboratories. The gauge was comprised of a sealed glass tube that contained a six-inch strip on which successive layers of molecules had formed. To measure the thickness of film few millionths of an inch thick, the user need only compare the color of film with the molecular grades. The gauge could measure the thickness of a transparent or semi-transparent substances within one to twenty millionths of an inch as effectively as much more expensive optical instruments, a very effective device for physicists, chemists, and metallurgists.

Blodgett continued working in the field of surface chemistry. Within five years, she had found another practical application that stemmed from Langmuir's original studies: non-reflecting, or invisible, glass. Blodgett discovered that coating sheets of ordinary glass with exactly forty-four layers of one-molecule thick transparent liquid soap rendered the glass invisible. This overall layer of soap--four-millionths of an inch thick and one quarter the wave length of white light--neutralized the light rays coming from the bottom of the glass with those coming from the top so that no light was reflected. Since the transparent soap coating blocked only about one percent of the light coming in, invisible glass was perfect for use in optical equipment--such as cameras and telescopes--in which multiple reflecting lenses could affect performance.

Blodgett did not hold sole credit for creating invisible glass. Two days after she announced her discovery, two physicists at the Massachusetts Institute of Technology (MIT) publicized that they had found another method of manufacturing non-reflecting glass using calcium fluoride condensed in a vacuum. Both groups of scientists, however, were concerned that their coatings were not hard and permanent enough for industrial use. Using some Blodgett's insights, the MIT scientists eventually found a more appropriate method of producing invisible glass. Today, the fruits of Blodgett's discovery can be found in almost all lenses used in cameras and other optical equipment, as well as automobile windows, showcases, eyeglasses, picture frames, and submarine periscopes.

During World War II, GE moved away from studies such as the one that lead to invisible glass in favor of tackling problems with more direct military applications. Following suit, Blodgett temporarily shelved her glass research, but did not move far from the field of surface chemistry. Her wartime experiments lead to breakthroughs involving plane wing deicing; she also designed a smoke screen that saved numerous lives during various military campaigns.

When the war ended, Blodgett continued doing research that had military ramifications. In 1947, for example, she worked with the Army Signal Corps, putting her thin film knowledge to use by developing an instrument that could be placed in weather balloons to measure humidity in the upper atmosphere. As Blodgett worked, plaudits for her research continued to pour in. Along with receiving numerous honorary degrees, Blodgett won the 1945 Annual Achievement Award from the American Association of University Women for her research in surface chemistry. In 1951, she accepted the Francis P. Garvan Medal from the American Chemical Society; that same year, Blodgett also had the distinction of being the only scientist honored in Boston's First Assembly of American Women in Achievement. To top off the year, Schenectady decided to honor its own by celebrating Katharine Blodgett Day.

Blodgett spent all of her adult life in the home she bought overlooking her birthplace. She was active in civil affairs in her beloved Schenectady, serving as treasurer of the Travelers Aid Society. Blodgett summered in a camp at Lake George in upstate New York, where she could pursue her love of gardening. She also enjoyed amateur astronomy, collecting antiques, and playing bridge with her friends. Blodgett died at her home on October 12, 1979, at the age of eighty-one.