Chien-Shiung Wu | Biography

Chien-Shiung Wu is perhaps the most respected female physicist in America. She was instrumental in the research that earned two of her colleagues, Dr. Tsung Dao Lee and Dr. Ning Yang, the Nobel Prize in Physics. Wu was born in Shanghai in 1915 and was raised in the nearby town of Liu Ho. Her father, Zong-Yee Wu, was the principal of the local elementary school, and he brought to his children a love of books, knowledge, and the arts; he also recognized the changes in the political and social landscape of China and prepared his children for them. Chien-Shiung went to high school in Soochow, where she studied English and science and decided to become a physicist. After graduation she enrolled at the National Central University, a government-funded school at Nanking. She received her B.S. in physics in 1936. Once she had graduated from the National Central University, Wu had exhausted China's scientific resources. No graduate program for physics existed in her country so she came to the United States in the fall of 1936 and enrolled at the University of California in Berkeley. This was an exciting time at the Berkeley laboratory: Dr. Ernest Orlando Lawrence was the new director and was developing there the first cyclotron. Wu was very fortunate in that she was studying under Lawrence as he conducted the research that would ultimately win him a Nobel Prize. In the late 1930s, Lawrence's laboratory was the site of some of the world's finest young physicists. Wu quickly adapted to her new environment. She was given a teaching position in her second semester. Wu also met there a fellow graduate student named Luke Cha-Liou Yuan, whom she eventually married. She was given a position as Dr. Lawrence's research assistant, and in her last year she was elected to Phi Beta Kappa. She received her Ph.D. in 1940. Research continued at the Berkeley laboratory, and Wu remained there after graduation. In 1942, however, Lawrence's laboratory was enlisted to aid the war effort; Wu, who chose to pursue pure research, soon accepted a teaching position at Smith College. At the end of her first year there she received an invitation to teach nuclear physics at Princeton; this was an unprecedented event, as Princeton frowned upon females addressing its male student body--particularly in the sciences. Though she accepted the position, her stay at Princeton ended after just a few months, for in March of 1944 she was asked to join the Manhattan Project team at Columbia University. This time she was very eager to contribute to the war effort, and she spent the next two years developing instruments to detect radiation. After the war Wu became a research associate at Columbia, where she studied the spectra of beta decay (which had been the subject of her doctoral thesis). She was made associate professor in 1952 and began to earn a reputation as an outstanding researcher. In 1956, she was asked to assist doctors Lee and Yang in their experiments. Lee and Yang were concerned with the validity of a concept of nuclear physics known as the principle of parity. It states that, on a nuclear level, an object and its mirror image will behave the same way. To understand this principle, imagine standing in front of a mirror while holding a lidded jar. Turn the lid clockwise and it comes off; meanwhile, your mirror image turns the lid counterclockwise, also removing the lid. In nuclear physics, a spinning nucleus emits particles as it decays; the principle of parity simply removes the mirror, asserting that the particles will be emitted no matter which way the nucleus spins. In 1952, a new particle called K-meson was discovered. Strangely, it did not seem to behave in the manner described by the principle of parity. This was unheard of, since the principle of parity had been universally accepted for more than thirty years. To doubt its validity was akin to disbelieving the law of gravity . Still, Drs. Lee and Yang announced that the parity principle was flawed. They suggested two types of experiments to disprove the theory and asked Wu to perform them. By cooling a decaying nucleus of cobalt 60 to 0.01 degrees Kelvin she was able to manipulate its spin. She then used a scintillation counter to observe the number of electrons emitted. Wu found that many more electrons were emitted as the nucleus spun one direction than in the other--thus disproving the principle of parity. Lee and Yang were awarded the Nobel Prize for their hypothesis, and they acknowledged Wu as being instrumental in its realization. Wu herself has received numerous accolades for her work. She was the seventh woman to join the National Academy of Sciences and the first woman to be granted an honorary doctorate in science from Princeton University in 1958. She is also a member of Academia Sinica, the Academy of Sciences of China.