Soddy, Frederick (sŏd`ē), 1877–1956, English chemist. He worked under Lord Rutherford at McGill Univ. and with Sir William Ramsay at the Univ. of London. After serving (1910–14) as lecturer in physical chemistry and radioactivity at the Univ. of Glasgow, he was professor of chemistry at the Univ. of Aberdeen (1914–19) and at Oxford (1919–36). He was especially noted for his research in radioactivity. With others he discovered a relationship between radioactive elements and the parent compound, which led to his theory of isotopes; for this work he won the 1921 Nobel Prize in Chemistry. His scientific books have become classics and include The Interpretation of Radium (1909, rev. ed. 1922), Matter and Energy (1912), The Chemistry of the Radio-Elements (2 parts, 1911–14), and Atomic Transmutation (1953). An advocate of technocracy and of the social credit movement, he wrote several books setting forth his political and economic views.

Soddy, Frederick

(born Sept. 2, 1877, Eastbourne, Sussex, Eng.—died Sept. 22, 1956, Brighton, Sussex) British chemist. He worked with Ernest Rutherford to develop a theory of the disintegration of radioactive elements. In 1912 he was among the first to conclude that elements might exist in forms (isotopes) of different atomic weights but indistinguishable chemically. In Science and Life (1920) he pointed out the value of isotopes in determining geologic age (see carbon-14 dating). For his investigations of radioactivity and isotopes, he received a 1921 Nobel Prize.