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| '''Wu Jianxiong''' the Chinese-born nuclear physicist (1912-1997), known in the West as Chien-Shiung Wu, who is remembered in her homeland for the precision of her experiments and for the contribution to physics that made her one of the most respected scientists of her generation.
| | #REDIRECT [[Chien-Shiung Wu]] |
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| == Early Life and Education in China ==
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| Wu Jianxiong was born on 31 May 1912 in Liuhe, a town near Shanghai in Jiangsu province. Her father, Wu Zhongyi, was a progressive educator who founded a school for girls, and he encouraged his daughter's interest in science at a time when few Chinese women pursued technical studies. She was educated in her father's school and then at a teacher-training institution in Suzhou.
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| She entered the National Central University in Nanjing in 1930, where she studied physics and graduated at the top of her class in 1934. She then taught for a year and worked as a research assistant, gaining the laboratory experience that would become the foundation of her career. Her teachers recognised an exceptional talent for careful measurement.
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| In 1936 she travelled to the United States to pursue graduate study, a journey that separated her from her family for years and placed her at the centre of world physics. She carried with her the rigour and self-discipline of her Chinese education and a determination to work at the highest level of her field.
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| == Graduate Study and a Scientific Career ==
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| Wu Jianxiong enrolled at the University of Michigan but soon transferred to the University of California, Berkeley, drawn by its strength in physics and by the presence of leading experimentalists. She worked under Ernest Lawrence and others on the new machines and techniques that were opening the atomic nucleus to study.
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| She completed her doctorate in 1940 and held positions at several institutions before joining Columbia University in 1944, where she worked on the Manhattan Project. Her task, conducted in secret, concerned the separation of uranium isotopes and the behaviour of radiation, and she helped to solve a problem that threatened the operation of the reactors used to produce material for the bomb.
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| She remained at Columbia for the rest of her career, becoming a professor and one of the leading experimental physicists in the world. She took American citizenship and adopted the name Chien-Shiung Wu in her professional life, but she retained close ties to China and to its scientific community throughout her years abroad.
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| == The Experiment on Parity ==
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| In 1956 the theoretical physicists Tsung-Dao Lee and Chen Ning Yang proposed that the weak nuclear interaction might violate parity, the symmetry between a process and its mirror image. The idea contradicted a principle long assumed to hold throughout physics, and it required a difficult experiment to test it in the decay of radioactive nuclei.
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| Wu Jianxiong designed and carried out the decisive experiment, cooling radioactive cobalt-60 to extremely low temperatures in a magnetic field so that the spins of the nuclei were aligned, and then measuring the direction in which the emitted electrons were given off. Her result, obtained in early 1957, showed a clear asymmetry, proving that parity is not conserved in the weak interaction.
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| The discovery overturned a cherished assumption and forced physicists to reconsider the symmetries of nature. Lee and Yang received the Nobel Prize in Physics in 1957 for the theoretical work, and though Wu's experiment was recognised worldwide as the crucial confirmation, she did not share the prize, a decision that remains a subject of debate about the recognition of experimental contributions.
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| == Wider Contributions and Recognition ==
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| Wu Jianxiong's work extended over many areas of nuclear and particle physics. She studied beta decay with unmatched precision, established the shape of the beta spectrum and tested the theory of the weak interaction against experiment, and she contributed to the understanding of the structure of the nucleon and of the decay of strange particles.
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| She wrote a standard account of beta decay that remained a reference for decades, and she trained many students who became leaders in their fields. She was elected to the National Academy of Sciences, became the first woman to serve as its president in a major professional society, and received the National Medal of Science and numerous other awards.
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| She was a persistent advocate for women in science and spoke candidly about the obstacles she had faced. Her lectures and addresses on discrimination were widely quoted, and she worked to open opportunities for those who followed her. She became a symbol of the possibility of excellence regardless of origin or gender.
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| == Influence and Legacy ==
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| Wu Jianxiong is honoured in China as a national figure of scientific achievement. Her life is taught as an example of the contribution that Chinese scientists have made to world science, and her name is attached to prizes, buildings and lectureships in her native land as well as abroad.
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| Her experiment on parity remains one of the classic tests of the laws of nature, and her precision measurements set a standard for the whole of experimental physics. The refusal of the Nobel committee to include her in the 1957 award has become a case study in the history of science and in the discussion of how credit is assigned.
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| She died on 16 February 1997 in New York. She is remembered as one of the greatest experimental physicists of the twentieth century, a Chinese-born scientist who reshaped the understanding of the fundamental forces and opened the way for those who came after her.
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| == See also ==
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| * Chien-Shiung Wu
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| * Parity
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| * Beta decay
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| * National Central University
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| == References ==
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| <ref name="r1">Chien-Shiung Wu, Beta Decay, Columbia University Press, 1965.</ref>
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| <ref name="r2">Tsung-Dao Lee and Chen Ning Yang, Question of Parity Conservation in Weak Interactions, Physical Review, 1956.</ref>
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| <ref name="r3">Magdolna Hargittai, Women Scientists: Reflections, Challenges and Breaking Boundaries, Oxford University Press, 2015.</ref>
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| <ref name="r4">Chiang Tsai-Han, Recollections of Chinese Physicists Abroad, Science Press, 2002.</ref>
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| <references />
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| [[Category:Physics]]
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| [[Category:Science]]
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| [[Category:United States]]
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