He was the son of a minister and the grandson of one of the pioneers who originally settled the area. Following his early education in rural schools and high school graduation in 1911, Urey taught for three years in country schools—first in Indiana and then in Montana. By 1914, he had earned enough tuition money to enroll in the University of Montana, from which he received his B.S. degree in zoology in 1917. He spent the next two years as an industrial research chemist, assisting in the manufacture of explosives for use in World War I before returning to Montana to teach chemistry.
Urey entered the University of California in 1921 and received his Ph.D. in chemistry in 1923. His doctoral research involved the use of spectroscopic techniques to study the entropy and heat capacity of gases. With funding from an American-Scandinavian Foundation fellowship, Urey traveled to Denmark and spent a year doing postdoctoral research under Niels Bohr at the Institute of Theoretical Physics of the University of Copenhagen. Upon returning to the United States in 1925, he became an associate professor in chemistry at Johns Hopkins University.
In 1929, Urey accepted an appointment as an associate professor in chemistry at Columbia University. There, in 1931, while engaging in research on diatomic gases, he devised a method to concentrate any possible heavy hydrogen isotopes by the fractional distillation of liquid hydrogen. To obtain an identifiable amount of heavy hydrogen, or deuterium, Urey exploited the fact that the suspected isotope should evaporate at a slightly slower rate than ordinary hydrogen. He carefully distilled approximately 4 meters of liquid hydrogen down to a volume of 1 milliliter. He then detected the presence of deuterium with spectroscopic analysis. His efforts confirmed the existence of deuterium (D), the nonradioactive heavy isotope of hydrogen that forms heavy water (D2O). As a result of this important discovery, Urey received the 1934 Nobel Prize in chemistry. Later that year, he also became a full professor at Columbia and received the Willard Gibbs Medal of the American Chemical Society.
From 1940 to 1945, Urey served as the director of war research on the Atomic Bomb Project at Columbia University. As part of the Manhattan Project during World War II, Urey worked primarily on uranium isotopic enrichment efforts. His research efforts also led to an important large-scale technique for obtaining deuterium oxide (heavy water)—a substance useful as a neutron moderator in nuclear reactors fueled by natural uranium.
Following World War II, he joined the Enrico Fermi Institute of Nuclear Studies at the University of Chicago and served as a distinguished professor of chemistry at the university until 1955. In the early 1950s, Urey pursued several new areas of study. He made an exciting contribution to the emerging field of planetary sciences, for example, by conducting one of the first experiments in exobiology—a classic experiment now widely known as the “Urey-Miller experiment.” He began to investigate the possible origins of life on Earth and elsewhere in the universe from an “extraterrestrial” chemical perspective. He summarized some of his basic ideas in the classic 1952 book The Planets: Their Origin and Development. In 1953, together with his graduate student, Stanley Miller (b. 1930), Urey performed his classic exobiology experiment. Urey and Miller created gaseous mixtures simulating Earth’s primitive atmosphere and then subjected these mixtures to various energy sources, such as ultraviolet radiation and lightning discharges. Within days, life-precursor organic compounds, known as amino acids, began to form in some of the test beakers.
Late in life, Urey accepted a position at the University of California in San Diego. He moved to California in 1958 and remained with the university until he retired in 1970. His research interest focused on a determination of paleotemperatures. Urey devised a clever way to estimate the temperatures in ancient oceans by examining the isotopic abundance of oxygen-18 in carbonate shells. His technique is based upon the fact that the calcium carbonate in seashells contains slightly more of the isotope oxygen-18 than oxygen-16 and that the ratio depends on the ocean temperature when the shell formed. Urey died on January 5, 1981, in La Jolla
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