Discovery of Carbon-14

Date: February 27, 1940 • Location: Washington, United States

American biochemists Martin Kamen and Sam Ruben discovered carbon-14, a radioactive isotope of carbon, which is now used extensively as the basis of the radiocarbon dating method to date archaeological and geological samples.

Martin David Kamen was an American chemist who, together with Sam Ruben, co-discovered the synthesis of the isotope carbon-14 on February 27, 1940, at the University of California Radiation Laboratory, Berkeley. He also confirmed that all of the oxygen released in photosynthesis comes from water, not carbon dioxide, in 1941.