Niels Bohr (1885–1962) was a Danish physicist known as the first to apply quantum theory to the study of atomic and molecular particles. He is also known for proposing the liquid model of the atomic nucleus and for formulating the Bohr theory of the atom. Bohr received a doctoral degree from the University of Copenhagen in 1911. He studied under J. J. Thomson at Cambridge University in England, but, when he learned that Thomson was not interested in his work, Bohr left to work under Ernest Rutherford in Manchester, England. There, Bohr distinguished himself by formulating the Bohr atomic model. He returned to Copenhagen in 1912 and in 1921 was named director of the Institute for Theoretical Physics. Under his direction, the Institute soon gained an international reputation for research in quantum theory and atomic physics. Bohr’s principle of complementarity offered a theoretical basis for quantum physics, which became widely accepted among many scientists, although Albert Einstein continued to dispute it. Bohr’s ground-breaking ‘‘liquid drop’’ model of the atomic nucleus and his ‘‘compound nucleus’’ model of the atom led other scientists to the discovery of nuclear fission. With the outbreak of World War II, Nazi Germany invaded Denmark, as a result of which Bohr and his family fled the country for England and then the United States. He worked on the Manhattan Project in Los Alamos, New Mexico, which developed the first atomic bomb. However, Bohr expressed concern throughout his life about the threat to humanity posed by nuclear warfare.
Sir James Chadwick
James Chadwick (1891–1974) was an English physicist credited with the discovery of the neutron, for which he received a Nobel Prize in 1935. Chadwick worked with Ernest Rutherford at the Cavendish Laboratory in Cambridge, England, in researching properties of the atomic nucleus. In 1945, he received the honor of being knighted for his accomplishments.
Arthur Compton (1892–1962) was an American physicist who shared the Nobel Prize for Physics in 1927 for his research on X rays. Compton received his doctorate from Princeton University in 1916. In 1920, he was made head of the department of physics at Washington University in St. Louis, Missouri. Compton’s research helped to make legitimate Einstein’s quantum theory, which was not yet widely accepted among scientists. In 1923, Compton became professor of physics at the University of Chicago, a post that he retained until 1945. He became the chairman of the committee of the National Academy of Sciences that in 1941 conducted research into the potential development of nuclear weapons, ultimately organizing the Manhattan Project. Compton worked on the Manhattan Project as the director of the University of Chicago Metallurgical Laboratory from 1941 to 1945.
Albert Einstein (1879–1955) was a German- Jewish physicist whose theories of relativity forever changed scientific approaches to space, time, and gravity. Einstein was awarded the Nobel Prize for physics in 1921. After Hitler came to power in 1933, Einstein fled Nazi Germany, eventually taking a post at the Institute for Advanced Study at Princeton University in New Jersey, where he remained for the rest of his life. In 1939, Niels Bohr alerted Einstein to the possibility that Germany could develop an atomic bomb. Bohr asked Einstein to write a letter to President Franklin D. Roosevelt, suggesting that the United States initiate research on an atomic bomb. Einstein, however, was not involved in the research carried out by the Manhattan Project and was not even aware of the successful development of the atomic bomb until after it was dropped on Hiroshima. In the wake of this event, Einstein became a vocal advocate for world peace and the prevention of further nuclear warfare.
Enrico Fermi (1901–1954) was an Italian-born physicist who won the Nobel Prize for physics in 1938 for his research on nuclear fission. Fermi earned a doctoral degree at the University of Pisa for his research on X rays. In 1926, he became a professor of theoretical physics at the University of Rome, where he was instrumental in developing a community of brilliant young physicists. On the pretext of traveling to Sweden to receive his Nobel Prize, Fermi fled fascist Italy with his family and settled in the United States. In New York City, Fermi met with other nuclear physicists, eventually becoming a part of the Manhattan Project. Based at the University of Chicago, he developed the first self-sustained nuclear chain reaction, which quickly lead to the making of the first atomic bomb. He became an American citizen in 1944 and, in 1946, was named professor of Nuclear Studies at the University of Chicago.
Richard Feynman (1918–1988) was an American theoretical physicist who received the Nobel Prize for physics in 1965 for his work on the theory of quantum electrodynamics. Feynman received his doctorate from Princeton University in 1942. From 1941 to 1942, he worked on the Manhattan Project in Princeton, joining the laboratory at Los Alamos, New Mexico, in 1943. Feynman was among the youngest scientists to hold a leadership position at Los Alamos. From 1945 to 1950, he worked as an associate professor at Cornell University, and from 1950 until his retirement he worked as a professor of theoretical physics at the California Institute of Technology. Feynman is considered one of the most brilliant scientific minds of the twentieth century.
Otto Frisch (1904–1979) was an Austrian-born physicist who worked on the Manhattan Project at Los Alamos, New Mexico. Frisch earned his doctorate degree at the University of Vienna in 1926. He worked with his aunt, the physicist Lise Meitner, together discovering and naming uranium fission in 1939. After the War, Frisch became director of the nuclear...
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