Chien-Shiung Wu was a Chinese-American experimental physicist. Wu was born in 1912 in Taicang, Jiangsu province, China. Her father was a passionate reader and fostered an educational environment of literature at home. She attended an elementary school for girls that was founded by her father. At the age of 11 she attended the Suzhou Women’s Normal School No. 2, a boarding school that held additional classes for teacher training. The admission for the teacher training program covered tuition and board and guaranteed a job upon graduation, thus it was highly competitive. Although her family could have afforded to pay for the program, Wu chose to compete for admission and placed 9th among 10,000 applicants.
Chien-Shiung Wu graduated in 1929 at the top of her class. She was admitted to the National Central University in Nanjing. At the time, teacher training students continuing on to university were required to serve as schoolteachers for one year. Wu opted for a public school in Shanghai. The president of the school was Hu Shih, a philosopher whose class she took while teaching.
Wu studied physics and then mathematics at National Central University from 1930-1934. She was involved in student politics, with tensions between Japan and China rising at the time. Her fellow students elected her to leadership positions because they felt that her top student status would protect her from political trouble with authorities. She led protests during her time as a student, including a sit-in at the Presidential Palace in Nanjing.
Wu pursued graduate studies in physics at Zhejiang University. She then worked as a researcher at the Institute of Physics of the Academia Sinica. Wu’s supervisor encouraged her to earn her PhD abroad, at the University of Michigan. Wu embarked for the United States to attend the University of Michigan in 1936, on the SS President Hoover. Her parents accompanied her to the port. It was the last time she ever saw them.
Upon arriving in America, Chien-Shiung Wu visited the University of California, Berkeley. There she met the grandson of Yuan Shikai (the first President of the Republic of China and self-proclaimed Emperor of China). Yuan was a physicist, who showed Wu the radiation laboratory of soon to be Nobel Prize for Physics winner Ernest O. Lawrence. Wu was impressed by the research being done at Berkeley. She had heard that women had fewer opportunities at the University of Michigan and chose to study at Berkeley instead. Although the academic year had all ready started, the head of Berkeley’s physics department offered her a place in the graduate school.<br>After her first year at Berkeley, Wu applied for a scholarship but was denied, possibly because of the strong prejudice against Asian students. Her research at Berkeley commenced at an impressive pace. Wu’s thesis had two parts. The first was concerned with breaking radiation, that is the electromagnetic radiation produced by the deceleration of a charged particle when deflected by another charged particle. This was her foundational research of beta decay, a subject she would become an authority on. The second part of her thesis involved the radioactive isotopes xenon, produced by the nuclear fission of uranium.
Chien-Shiung Wu received her PhD in 1940. She was also admitted to the Phi Beta Kappa U.S. Academic Honor Society. Despite her credentials and strong letters of recommendation, she was not able to get a faculty position at Berkeley. Instead, she continued her work at the Radiation Laboratory as a post-doctoral fellow.
In 1942, Chien-Shiung Wu married Yuan Shikai at the home of Yuan’s academic supervisor, Robert Millikan, the president of Caltech. Neither of their families could be in attendance due to the outbreak of the Pacific War. The couple then moved to the East Coast, where Wu took on a faculty position at Smith College, a private women’s college in Massachusetts. Yuan got a job working on radar technology for RCA. Wu’s position did not provide an opportunity for research, it was teaching only. She found this frustrating. She wrote letters of appeal with high letters of recommendation to a number of universities on the East Coast. Smith College raised her salary and made her an associate professor, but Wu accepted a job at Princeton University as an instructor to naval officers instead.
Wu joined the Substitute Alloy Metals Laboratories of the Manhattan Project at Columbia University in 1994. She returned to work at Princeton on the weekends, spending her weeks in a dorm at Columbia. The SAM laboratories were working with gaseous diffusion for uranium enrichment. One of her jobs was to help develop radiation detection equipment. In September of 1994 the Manhattan Project’s District Engineer reached out to Wu. The new B Reactor site in Hanford, Washington, was shutting down unexpectedly. They contacted Wu because they suspected the problem was caused by xenon, whose radioactive isotopes Wu had studied at Berkeley. The problem was solved with the help of an unpublished paper about the the radioactive isotopes of xenon that Wu had typewritten.
In 1945 Wu accepted a position as an associate research professor at Columbia. Communication with China was restored so Wu finally received a letter from her parents, but she could not visit them due to the outbreak of the Chinese Civil War. In 1947 she gave birth to Vincent Yuan. Who grew up to become a physicist as well.
In 1949 Yuan joined the Brookhaven National Laboratory. Wu and her family moved to Long Island. The communists came to power in China that year, and Wu’s father told her not to visit. This prompted Wu to go through with becoming an American Citizen in 1954. In 1952 Wu had become an associate professor at Columbia. She became a full professor in 1958, and a distinguished professor of physics in 1973.
Wu’s experimental work in beta decay helped prove that the law of conservation of parity was invalid, and that parity is not conserved under weak nuclear reactions. This discovery was a major contribution to particle physics and the development of the Standard Model. In recognition of this work, Wu’s colleagues were awarded the Nobel Prize for Physics in 1957. Her role in the discovery was not honored until she was awarded the inaugural Wolf Prize, in 1978. Wu continued to make major contributions to science through researching entangled photons of quantum physics, sickle-cell disease, and magnetism.
Due to the United States imposition of severe travel restrictions to communist countries, Wu was unable to attend the funerals of her older brother, mother, and father. In 1965 she saw her uncle and younger brother again during a trip to Hong Kong. After President Nixon visited China in 1972, the relations between the two countries improved, and Wu proceeded to visit China several times. Later in life Wu became more politically outspoken, protesting against gender discrimination, the Tiananmen Square massacre of 1989, and political imprisonments in Taiwan. During a symposium at MIT in 1964, she asked her audience “I wonder, whether the tiny atoms and nuclei, or the mathematical symbols, or the DNA molecules have any preference for either masculine or feminine treatment.” She preferred to be called Professor Wu rather than Professor Yuan. In 1975, her pay at Columbia was adjusted to match those of her male colleagues. In 1978 she was awarded a Wolf Prize in Physics, in part because she was deserving of a Nobel Prize but hadn’t actually received one. Chien-Shiung Wu retired in 1981, and became a professor emerita at Columbia. In 1997, at the age of 84 Wu died after suffering a stroke. Her ashes were buried in China, in the courtyard of the school she attended as a child, which her father had founded.