|Born||May 29, 1912
|Died||February 16, 1997 (aged 84)
New York City
|Institutions||Institute of Physics, Academia Sinica
University of California at Berkeley
|Alma mater||National Central University, China
University of California at Berkeley
|Doctoral advisor||Ernest Lawrence|
|Known for||parity violation experiments
Beta decay research
The Manhattan Project
|Notable awards||The Wolf Prize (1978)
The National Medal of Science (1975)
The Bonner Prize (1975)
Chien-Shiung Wu (simplified Chinese: 吴健雄; traditional Chinese: 吳健雄; pinyin: Wú Jiànxíong, May 29, 1912 – February 16, 1997) was a Chinese-American physicist with an expertise in the techniques of experimental physics and radioactivity. Wu worked on the Manhattan Project (in the process for enriching the uranium into the U-235 fissile metal), and performed very early experiments that contradicted the hypothetical "Law of Conservation of Parity". Her honorific nicknames included the "First Lady of Physics", the "Chinese Marie Curie", and "Madame Wu". She died after suffering her second stroke on February 16, 1997, at the age of 84.
Although Wu's ancestral family town is Taicang (in Jiangsu Province), Wu was born in 1912, in Shanghai. She was raised in Liu Ho, a town about 40 miles from Shanghai. Her father, Wu Zhongyi (吳仲裔), was a proponent of gender equality, and he founded the Mingde Women's Vocational Continuing School. Wu left her hometown at the age of 11 to go to the Suzhou Women's Normal School No. 2. Her mother was Fan Fuhua (樊復華), about whom little is known.
Chien-Shiung Wu was admitted to the National Central University of Mainland China in 1929. (This university was later merged the Nanjing University in 1949 in mainland China, with another branch relocated to Taiwan). According to the governmental regulations of the time, "normal school" (teacher-training college) students wanting to move on to the universities needed to serve as schoolteachers for one year. Hence in 1929, Wu went to teach in the Public School of China (中國公學), which had been founded by Hu Shi in Shanghai.
From 1930 to 1934, Wu studied in the Physics Department of the National Central University. For two years after graduation, she did graduate-level study in physics and also worked as an assistant at the Zhejiang University. After this, Wu became a researcher at the Institute of Physics of the Academia Sinica.
Chien-Shiung Wu decided that she wanted to and needed to continue her studies in physics to a higher level than was possible to do in China. Therefore, she started making applications to study at universities overseas, especially in California. Upon receiving a favorable response in 1936, Wu and her female friend, Dong Ruofen (董若芬), a chemist from Taicang, China, embarked on the long steamship voyage from China to the West Coast of the United States.
The two women most likely arrived at the large seaport of San Francisco, because Wu enrolled in graduate school at the University of California located then just in Berkeley, California, which is also on San Francisco Bay. After some time at the University of California, Wu's high abilities and good fortune found her a position as a graduate student under the supervision of Ernest O. Lawrence, who won the Nobel Prize for Physics in 1939 for his invention of the cyclotron atom smasher and the development of its applications in physics.
Under Dr. Lawrence, Wu made rapid progress in her education and her research, and she completed her Ph.D. degree in 1940.
Wu married the physicist Luke Chia-Liu Yuan, two years later, in 1942. They became the parents of one son, Vincent Yuan (袁緯承), who also became a physicist. Chia-Liu Yuan's grandfather was Yuan Shikai, the first President of the Republic of China and in his final days, a short-lived self-claimed Emperor of China.
The new Yuan family moved to the East Coast of the U.S., where Chien-Shiung Wu became a faculty member at first Smith College, then Princeton University in New Jersey for 1942－44, and finally at Columbia University in New York City, beginning in 1944 and continuing for many years after the war, all the way through 1980.
At Columbia University, Wu also did research and development for the Manhattan Project. She helped to develop the process for separating uranium metal into the U-235 and U-238 isotopes by gaseous diffusion. This was the process that was implemented on a gigantic scale at the K-25 Plant near Oak Ridge, Tennessee, whose construction began in 1944.
In her research at Columbia, Chien-Shiung Wu also worked to develop improved Geiger counters for measuring nuclear radiation levels. At Columbia Wu knew the Chinese-born theoretical physicist Tsung-Dao Lee personally. In the mid-1950s, Lee and another Chinese theoretical physicist, Chen Ning Yang, grew to question a hypothetical law in elementary particle physics, the "Law of Conservation of Parity" (see Parity (physics). Their library research into experimental results convinced them that this "Law" was valid for electromagnetic interactions and for the strong nuclear force. However, this "Law" had not been tested for the weak nuclear force, and Lee & Yang's theoretical studies showed that is was probably not true. Lee and Yang worked out the pencil & paper design of several experiments for testing the "Conservation of Parity" in the laboratory, and then Lee turned to Wu for her expertise in choosing one and then actually working out the actually hardware manufacture, set-up, and laboratory procedures for carrying out the experiment.
Chien-Shiung Wu chose to do this for an experiment that involved taking a sample of radioactive cobalt 60 and cooling to cryogenic temperatures with liquid gasses. Cobalt 60 is an isotope that decays by beta particle emission, and Dr. Wu was also an expert on beta decay. The extremely-low temperatures were needed to reduce the amount of thermal vibration of the cobalt atoms to practically nil. Also, Dr. Wu needed to apply a constant and uniform magnetic field across the sample of cobalt 60 in order to cause the spin axes of the atomic nuclei to all line up in the same direction. For this cryogenic work, Dr. Wu needed the expertise of the National Bureau of Standards in liquid gases to aid her, thus she traveled to Maryland with her equipment to carry out the experiments.
Lee and Yang's theoretical calculations predicted that the beta particles from the cobalt 60 atoms would be emitted asymmetrically if the hypothetical "Law of Conservation of Parity" proved invalid. Dr. Wu's experiments at the National Bureau of Standards showed that this is indeed the case: parity is not conserved under the weak nuclear interactions. This was also very soon confirmed by her colleagues at Columbia University in different experiments, and as soon as all of these results were published—in two different research papers in the same issue of the same physics journal—the results were also confirmed at many other laboratories and in many different experiments.
For their taking the lead in all of this, and for their theoretical work on the question of parity in the physics of subatomic particles, Lee and Yang were quickly awarded the Nobel Prize for Physics in 1957.
Chien-Shiung Wu's book titled Beta Decay (published 1965) is still a standard reference for nuclear physicists.
Chien-Shiung Wu's career presented a number of breakthroughs.
Wu was one of the first Chinese-American educators who returned to mainland China for visits in 1970s.
Wu won numerous honors and recognitions:
At the time of her death, Wu was Pupin Professor Emerita of Physics at Columbia.fuge
Chien-Shiung Wu (traditional Chinese: 吳健雄; pinyin: Wú Jiànxíong; May 29, 1912 – February 16, 1997) was a Chinese-born American physicist with an expertise in radioactivity. She worked on the Manhattan Project (to enrich the uranium fuel) and disproved the conservation of parity. Her nicknames included the “First Lady of Physics”, “Chinese Marie Curie,” and “Madame Wu.” She died after her second stroke on February 16, 1997.