Becquerel, Henri (1852-1908) French physicist. Becquerel was born in Paris. His early scientific and engineering training was at the Ecole Polytechnique and the School of Bridges and Highways. After completing his doctorate, he became a professor of physics, continuing the family tradition of his father and grandfather. He is most remembered as the discoverer of radioactivity in 1896. Following the discovery of X-rays in 1895, he began researching fluorescence in uranium salts. Through a bit of luck, Becquerel uncovered a new form of radiation coming from the salts, which was later found to be emanating from the nuclear disintegrations in the uranium atoms. In 1903, he shared the Nobel Prize for physics for his work on radioactivity with Pierre and Marie Curie.
Bohr, Niels (1885-1962) Danish physicist. Bohr came from a distinguished scientific family in Copenhagen, Denmark. After completing his Ph.D. in 1911, he spent four years with Ernest Rutherford at Manchester University. Using the experimental results of Rutherford and others, Bohr developed a theoretical model of the atom that was stable and explained many of the observed phenomena. In 1918 he became the director of the newly created Institute of Theoretical Physics. Bohr won the 1922 Nobel Prize for physics for “his services in the investigation of the structure of atoms and of the radiation emanating from them." Bohr made major contributions to the field of radioactivity, which led to the discovery and development of nuclear fusion. After World War II he spent much of his time working with scientists to initiate adequate controls for the proliferation of nuclear weapons.
Bragg, William Henry (1862-1942) British physicist. Bragg was born in England and graduated from Cambridge University studying under J.J. Thomson. He became a professor of mathematics and physics in Adelaide, Australia. He returned to England in 1909 to be a professor at Leeds University and University College. Much of his research was on X-ray crystallography in collaboration with his son, William Lawrence Bragg. The father and son team shared the 1915 Nobel Prize in physics in 1915. He continued his research investigating organic materials with X-rays.
Chadwick, James (1891-1974) British physicist. Chadwick was born in Macclesfield and was educated at the University of Manchester. After graduation in 1911, he remained as a graduate student under Ernest Rutherford. In 1913 he moved to Germany to work under Hans Geiger and was interred by the Germans for the duration of World War I. After the war he went to work for Rutherford at the Cavendish Laboratory and was the assistant director of research from 1922 until 1935. Chadwick is known for his discovery of the neutron in 1932. In 1936 he left the Cavendish and became a physics professor at Liverpool University. During World War II he was the head of the British mission to the Manhattan Project in Los Alamos, New Mexico. He received the Nobel Prize in physics in 1935 for his discovery of the neutron.
Cockcroft, John (1897-1967) British physicist. Cockcroft was born in northern England, entered Manchester University 1914 to study mathematics, but left the following year to serve in the military during World War I. After the war, he worked and continued his studies at Cambridge University, graduating with a degree in mathematics, and then worked under Ernest Rutherford at the Cavendish Laboratory. Cockcroft teamed with Ernest Walton to bombard nuclei of lithium with protons in 1932. They succeeded in generating the first nuclear transformation by artificial means, commonly called splitting the atom. During World War II, Cockcroft played a significant role in the development of radar. In 1951, Cockcroft and Walton received a Nobel Prize in physics “for their pioneer work on the transmutation of atomic nuclei by artificially accelerated atomic particles."
Figure – John Cockcroft, Ernest Rutherford, and Ernest Walton in 1932, shortly after they accelerated protons against a lithium target, splitting the lithium nucleus into two alpha particles.
Curie, Marie Sklodowska (1867-1934) Polish-French chemist. Born in Poland and educated in physics at the Sorbonne, in Paris, France, she married the scientist Pierre Curie and together they discovered the radioactive elements thorium, radium, and polonium. She became the first female professor at the Sorbonne. Received two Nobel Prizes for her work in the area of radioactivity. Spent much of her career after her husband’s death in 1906 in research at the Institute of Radium in Paris. During World War I, she was responsible for developing mobile X-ray machines to be deployed at field and established hospitals to aid doctors with diagnosis and treatment. She is ranked as one of the most important female scientists to have ever lived.
Figure – Marie and Pierre Curie in the laboratory in Paris.
Curie, Pierre (1859-1906) French physicist. Pierre was educated at the Sorbonne in Paris. In 1882 he became the head of the laboratory at the School of Industrial Physics and Chemistry until he was appointed professor of physics at the Sorbonne in 1904. In 1895 he married a graduate student from Poland named Marie Sklodowska. Pierre, with his brother, discovered the property of certain crystals called piezoelectricity and determined that ferromagnetic materials lose their magnetization at a certain temperature, known as the Curie point. He spent the rest of his life until his accidental death in 1906 working with his wife on the discovery of radioactive elements.
Gamow, George (1904-1968) Ukrainian-American physicist. Gamow was born in Ukraine and educated at the University of Leningrad where he obtained his doctorate in 1928. After working as a professor of physics in Denmark and England, he moved to the America to be professor of physics at George Washington University and the University of Colorado. Gamow made contributions to a wide area of physics research, most notably in the areas of nuclear and atomic physics, cosmology, and molecular biology. Gamow wrote many popular books on physics in which he conveyed the excitement of the revolution in physics that he had witnessed in his lifetime.
Geiger, Hans (1882-1945) German physicist. Geiger was born in Germany and studied physics at the universities of Munich and Erlanger. Then he took a position at Manchester University in England working for Ernest Rutherford. In 1912 he returned to Germany where he held several prominent university positions. Geiger was a pioneer in nuclear physics and developed several instruments and techniques for measuring radioactivity. In 1928 he worked with W. Muller to produce a radiation counter commonly know as the Geiger-Muller counter. Geiger worked with Ernest Marsden at the Cavendish Laboratory in 1909 on the fundamental experiment of scattering of alpha particles by a thin sheet of gold, leading to the Rutherford model of the atom.
Kapitsa (also spelled Kapitza), Pyotr (1894-1984) Russian physicist and engineer. Pyotr (or Peter) Kapitsa was born in Kronstadt, Russia, and was educated at the Polytechnic Institute and the Physical and Technical Institute in Petrograde. He was involved in magnetic research at the Cavendish Laboratory, England, working under Ernest Rutherford and receiving his Ph.D in 1923. He became the director of the Royal Society Mond Laboratory at Cambridge in 1930. During a visit to his homeland in 1934, Russian authorities detained him. He then organized the Institute for Physical Problems, at which he continued his research on strong magnetic fields, low temperature physics, and cryogenics. Kapitsa’s most significant work in low-temperature physics was on the viscosity of the form of liquid helium known as He-II. In 1978, Kapitsa was awarded for his work in low-temperature physics with a Nobel Prize.
Soddy, Frederick (1877-1956) British chemist. Soddy was born in Eastborne, United Kingdom, and was educated at the University College of Aberystwyth and Oxford Universities. After working with Ernest Rutherford in Canada and William Ramsey in London, he taught chemistry at various universities. Working with Rutherford from 1901 to 1903, they discovered that radioactive elements would change into other elements through a series of stages. He came up with the concept of the isotope, which are chemically identical elements with slightly different atomic numbers. He won the Nobel Prize in 1921 in chemistry for his work on the origins and nature of isotopes. After 1919, he became disillusioned with science and became a writer on social and economic issues.
Thomson, Joseph John “JJ” (1856-1940) British physicist. Thomson was born in Manchester, United Kingdom, and entered Owens College at age 14 to study engineering and the sciences. The then went to Cambridge University where he graduated in 1876 and remained at the university in various positions until his death. Thomson built the Cavendish Laboratory into a premier research institution. He is most remembered for his work with cathode rays and his determination that they are negatively charged fundamental particles we now call electrons. He received the Nobel Prize in 1906 for his work on the conduction of electricity through gases. He was knighted in 1908.
Walton, Ernest (1903-1995) Irish physicist. Walton was born in Ireland and studied at the Methodist College, Belfast, where he excelled in science and mathematics. He graduated from Trinity College, Dublin, in 1926 in mathematics and experimental science. In 1927 he worked under Ernest Rutherford at the Cavendish Laboratory at Cambridge, England. There he worked with John Cockcroft to accelerate particles leading to splitting of the atom. In 1934, Walton completed his Ph.D. from Cambridge and returned to Dublin as a fellow of Trinity College. In 1951, Cockcroft and Walton received a Nobel Prize in physics “for their pioneer work on the transmutation of atomic nuclei by artificially accelerated atomic particles."