Nuclear physicist. Frank Friedman Oppenheimer was born in New York City to German immigrants and textile importers, and brother of J. Robert Oppenheimer (1904-1967), Oppenheimer attended Johns Hopkins University, studied physics at Cambridge, and received his PhD from the California Institute of Technology (1939); Thesis: Beta Ray Spectra. Oppenheimer became a noted nuclear and cosmic-ray physics researcher and helped develop the atomic bomb as a member of the Manhattan Project-he was present with his brother at the Trinity explosion of the world's first atomic bomb on July 16, 1945 in New Mexico. After the end of World War II, Frank Oppenheimer joined the faculty of the University of Minnesota, and was dismissed from that institution in 1949 after testifying before the House Un-Ameican Activities Committee that at one time he was a member of the American Communist Party. For the next several years he raised cattle in Pagosa Springs, Colorado. Oppenheimer taught in a rural Colorado high school from 1957 to 1959. Then, from 1959 to 1979, Oppenheimer was appointed as a professor in the Department of Physics at the University of Colorado at Boulder. In 1965, Professor Frank Oppenheimer was awarded a Guggenheim Fellowship to study and research bubble chamber dynamics at University College in London. In 1969 he moved to San Francisco and with his wife Jackie established the Exploratorium, a highly popular science museum (known as "the museum of science, art, and human perception"). Publications include: Working Prototypes: Exhibit Design at the Exporatorium (co-author, 1986). Married to Jaquenette Yvonne "Jackie"Quann (m 1936), and then, Mildred "Millie" Daielson (m 1982).