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National Museum of Nuclear Science & History

Manhattan Project Spotlight: Isabella Karle

When Isabella Karle walked into her chemistry class at Wayne State University at the beginning of her freshman year in 1940, she was the only girl in the class. “That didn’t seem to matter,” says Karle. Her love of chemistry led to work on the Manhattan Project, a renowned career in the field of crystallography, and countless awards for revolutionary work on crystal structures.

Isabella’s passion for learning began at an early age. Her parents, Zygmunt A. Lugoski and Elizabeth Graczy, emigrated from Poland during the early twentieth century and moved to Detroit, where Isabella was born. When her mother decided to open a restaurant in the early 1920s, she taught Isabella how to add numbers. “I soon became the accountant,” says Isabella. “Fresh meat was delivered every day and the butcher left the bill that had to be paid once a week. So once a week, I added up all the numbers of the money that was owed to him.”

By the time Isabella began elementary school, she could already read and write in Polish and do arithmetic. “The teachers used to wonder how I did that since I didn’t speak English,” says Isabella, with a laugh. After skipping several grades in middle school, Isabella finally arrived in high school, where she was introduced to science.

“I read that if I had wanted to go to a university, I would have to have some coursework in high school in science,” says Isabella. She picked chemistry. “That was a fortunate choice because I thought that the teacher, who was a female chemistry teacher – unusual in those days – was a very good teacher. And she was the one who sparked a very intense interest in what I was learning in her class.”

After attending Wayne State University for one semester, a former high school teacher reached out to Isabella and encouraged her to take a statewide examination for a chance to win a scholarship to the University of Michigan. Isabella placed fourth in the state.

As soon as Isabella arrived in Ann Arbor, she enrolled in the chemistry program. That is where she met her match. “I walked into the physical chemistry laboratory and there’s a young man in the desk next to mine with his apparatus all set up running his experiment,” remembers Isabella. “I don’t think I was very polite about it. I asked him, how did he get in here early and have everything all set up? He didn’t like that. So we didn’t talk to each other for a while.”

That young man was Jerome Karle, a Brooklyn native who attended City College and then Harvard before moving to Michigan to pursue a Ph.D. in chemistry. Like Isabella, Karle was “an exceptional student who got through school in record time” and had a passion for chemistry. As two of the top students in the chemistry lab, Isabella and Jerome regularly tried to beat each other’s scores. The two also began spending time together outside the classroom. They married in 1942.

With the war in Europe already raging, Jerome was selected for a secret project in Chicago that could help the Allies win the war. “I didn’t know what he was doing except that it was chemistry and it was exciting,” recalls Isabella. After completing her Ph.D. in 1943, she too was invited to work on the secret project.

When Isabella arrived in Chicago that summer, she soon discovered what scientists were working on. “It turned out to be the plutonium project in what was called New Chemistry at the University of Chicago,” says Isabella. “My objective was to find out how plutonium behaves with other chemicals and how to synthesize a new compound of plutonium chloride with no impurities.”

At twenty-three years of age, Isabella was one of the youngest scientists at the laboratory and one of only a handful of women. “I looked like any other student at the University—I still wore pigtails and walked around campus freely,” she remembers.

Still, security around the top-secret project remained tight. When guards discovered that Isabella was carrying samples of plutonium chloride across campus to have them examined by a fellow physics professor, they assigned a security detail. “I would walk across campus with these samples in my pocket and I had two guards walk with me. Everybody who looked at us thought that was peculiar,” says Isabella.

The lab at Chicago also had strict safety standards. “Each one of us every day had to take a great big tablet like that of calcium chloride,” recalls Isabella. “It was reasoned that our bones are mostly calcium and radium displaces the calcium in the bones if you’re exposed to radium.” Employees also wore radiation badges and had meters that would ring in the case of abnormal exposures.

Even with such standards in place, there were a few close calls. Isabella recalled one instance involving the laboratory’s Coca-Cola machine. “The delivery man who delivered the syrup couldn’t find his hose and funnel and he didn’t want to go through security again, so he looked into the closest laboratory and saw a length of rubber pipe that would suit him quite well,” says Isabella. “He poured the syrup through this rubber hose into the container for the syrup, but what he didn’t realize is that he picked up a very radioactive piece of laboratory equipment. The syrup went through it and, of course, contaminated the whole machine.”

Fortunately, Isabella walked by the machine before anybody else had used it. “It registered on my meter, bells went off, and it was discovered where the radiation was and how it was contaminated.” The next day, there was a brand new Coke machine. This time, the coke came in bottles.

After the Manhattan Project, Isabella and Jerome began a lifetime of collaboration. In 1946, both were invited to join the Naval Research Laboratory, where they began working on a new method to determine the structure of complex biological molecules. Jerome worked on the experimental equations needed to analyze the molecules while Isabella provided the experimental data to prove that they worked.

With the help of some of IBM’s earliest computing machines, Jerome and Isabella were able to verify their equations. This new methodology drastically improved scientists’ ability to analyze and understand complex biological molecules and contributed to the development of new pharmaceuticals.

In 1985, Jerome and colleague Herbert Hauptman were awarded the Nobel Prize in chemistry for their work on the mathematical equations. Despite her experimental work on the project, the Nobel Committee ignored Isabella’s contribution. No one was more upset than Jerome, says Isabella. “But I told him to forget about it—I had enough awards as it was.”

Isabella won a number of prizes for her experimental work, including the National Medal of Science, award by President Clinton; the Women in Science and Engineering Lifetime Achievement Award; and the Navy’s Superior Civilian Service Award. “I enjoyed all the scientific work that I was involved in and I also enjoyed traveling around the world. Not all people are that fortunate.”