Harold Urey Essay, Research Paper
Harold Clayton Urey Papers
Harold Clayton Urey was a scientist of considerable scope whose discovery of deuterium
helped him win the Nobel Prize for Chemistry in 1934. Urey also made fundamental
contributions to the production of the atomic bomb through his development of the
isotope separation processes for the Manhattan Project. In the period following World
War II, Urey played an active part in advocating nuclear arms control, in promoting space
exploration and in the development of the newly created campus of the University of
California, San Diego.
Born in Walkerton, Indiana, on April 29, 1893, Harold Urey was the son of Samuel
Clayton and Cora Rebecca (Reinohl) Urey. His early schooling took place in rural Indiana.
After graduating from high school he taught in country schools in Indiana and Montana
for three years. In 1914 he entered Montana State University where he majored in zoology
and minored in chemistry. He received a Bachelor of Science degree in 1917 and worked
as an industrial chemist in Philadelphia until the end of World War I. He then returned to
Montana as an instructor in the department of chemistry, where he remained for two years
before pursuing a doctorate at the University of California, Berkeley.
At Berkeley Urey studied thermodynamics and worked with Gilbert N. Lewis. Urey’s
doctoral research dealt with the rotational contributions to the heat capacities and
entropies of gases, a subject not well understood at the time. He was able to form
calculations which led directly to the present methods of calculating thermodynamic
functions from spectroscopic data.
In 1923 Urey attended the Institute for Theoretical Physics at the University of
Copenhagen. There he studied under Niels Bohr, who was conducting seminal work in the
theory of atomic structure. During this period Urey became involved in the international
development of atomic and molecular physical science, and he made the acquaintance of
prominent scientists of the time, including Werner Heisenberg, Wolfgang Pauli and Georg
von Hevesy. Also in Europe Urey met Albert Einstein, who became a life-long friend.
Dr. Urey returned to the United States in 1924, and for the next five years he served as
Associate in Chemistry at Johns Hopkins University. From 1929 to 1934 he held the
position of Associate Professor of Chemistry at Columbia University. His research during
these years was principally devoted to experimental and theoretical work in spectroscopy
and quantum mechanics. At this time he collaborated with A.E. Ruark in writing ATOMS,
MOLECULES AND QUANTA, one of the earliest books on quantum mechanics. This
work eventually became one of the standard texts on the subject.
On a visit to Seattle, Dr. Urey met Frieda Daum, a bacteriologist working in a doctor’s
office. Ms. Daum’s sister had been a friend of Urey’s at Montana. Married in 1926, Frieda
and Harold Urey had four children: Gertrude Elizabeth, Frieda Rebecca, Mary Alice, and
In 1931 Dr. Urey announced that he, together with George M. Murphy and Ferdinand G.
Brickwedde, had discovered the existence of heavy water, in which the molecules consist
of an atom of oxygen and two atoms of heavy hydrogen or deuterium. The identification
of deuterium has been called one of the foremost achievements of modern science and has
had a significant effect on research in physics, chemistry, biology, andmedicine. As the
discoverer of this isotope, Urey was awarded the Nobel Prize for Chemistry in 1934. His
Nobel Prize address, delivered on February 14, 1935, was entitled, “Some
Thermodynamic Properties of Hydrogen and Deuterium.”
Urey became the first editor of the JOURNAL OF CHEMICAL PHYSICS in 1933. The
American Institute of Physics published this journal in response to the developing interest
in sub-atomic and molecular spectroscopy and structure. Urey remained editor until 1941,
establishing the journal as a leader in the newly created field of chemical physics.
For the next decade, Dr. Urey occupied himself with the experimental and theoretical
aspects of isotopic chemistry, and he soon became the leading authority on the subject. In
1934 he was appointed to the position of Professor of Chemistry at Columbia University,
and from 1939 to 1942 he was the executive officer of the Chemistry Department at
Columbia. Urey’s scientific work became increasingly concerned with the separation of
isotopes. In 1940 the United States government recruited him to serve as director of the
program, established at Columbia, for separation of uranium isotopes and deuterium oxide
During World War II, Dr. Urey applied his work in uranium isotope separation to the
development of the atomic bomb. The U.S. Army assumed responsibility for atomic
weapons development — eventually called the Manhattan Project — and General Leslie
Groves served as overall director of the effort. Dr. Urey was appointed to the position of
Director of War Research for the Special Alloy Materials (SAM) Laboratories at
Columbia, where he worked on the uranium separation problem. He also served as one of
three program chiefs in the Manhattan Project. Although awarded the Congressional
Medal of Merit for his contributions, Urey’s concern for the destructive consequences of
atomic weapons, and his aversion to secret work, prompted him to leave the project.
In response to the U.S. use of atomic bombs against Japan, Dr. Urey joined Albert
Einstein, Leo Szilard, and other scientists to form the Emergency Committee of Atomic
Scientists. This organization dedicated itself to enunciating the ethical and moral problems
involved in the use of atomic weapons. Urey also joined with physicist Leo Szilard to
oppose the U.S. military’s administration of atomic power and to advocate limitations in
the use of the atomic bomb.
In 1945 Urey joined the faculty of the University of Chicago and contributed his efforts to
the establishment of the Institute of Nuclear Studies, together with Enrico Fermi, Edward
Teller, Leo Szilard, Joseph Mayer, Maria Goeppert Mayer, and others. At Chicago, Urey
focused his attention on geochemistry and the problems of the cosmos. His work on the
measurement of the paleotemperatures of ancient oceans is considered one of the great
developments of the earth sciences. This work involved a wide scope of disciplines
ranging from Urey’s early biological interests to his studies of isotopic fractionation and
the history of the earth. While at Chicago, Urey wrote THE PLANETS: THEIR ORIGIN
AND DEVELOPMENT, in which he constructed the first systematic and detailed
chronology of the origin of the earth, the moon, the meteorites, and the solar system.
Urey participated in Operation Crossroads in 1946. This was a major atomic bomb test
carried out by the U.S. government at Bikini Atoll in the Pacific. As a scientific observer,
Urey joined other prominent scientists, including Roger Revelle, future director of Scripps
Institution of Oceanography.
In 1952 the trials of Ethel and Julius Rosenberg and Morton Sobell attracted Dr. Urey’s
attention. The Rosenbergs, accused of atomic espionage and given a highly publicized and
controversial trial, were eventually sentenced to death. Sobell, tried as a co-conspirator,
wasgiven a long prison sentence. These cases became causes celebres during in the
Postwar era. Reading the trial documents, Dr. Urey seriously questioned whether the
Rosenbergs and Sobell had received justice from the U.S. courts. He publicly expressed
his concern, urging clemency in letters to President Truman, the trial judge and the NEW
YORK TIMES. Urey’s efforts brought him a flood of mail, some critical, some hateful,
some favorable. Among the favorable responses was a letter from Albert Einstein, who
wrote to Urey: “Your intervention in the Rosenberg case has been one of my most
heartening experiences in the human sphere.” This letter is filed with Einstein
correspondence, box 29 of the papers.
In 1958 Urey accepted a position at the University of California’s Scripps Institution of
Oceanography in La Jolla. Scripps director Roger Revelle was engaged in establishing a
general campus of the University in La Jolla, soon to become the University of California,
San Diego (UCSD). Revelle had urged Urey to take the Scripps post, and Urey provided
valuable assistance in developing the new campus. Many of Urey’s Chicago colleagues
also moved to UCSD, including Maria Mayer and Joseph Mayer. Leo Szilard came to La
Jolla as a fellow of the newly established Salk Institute.
At UCSD Urey formed the nucleus of the chemistry program, which later become a
leading center in the field of cosmochemistry. As Professor of Chemistry-at-Large, he
continued to teach and conduct active research on the campus. His studies extended over
a broad range of interests, including the geophysics of the solid earth, geochemistry, the
chronology of meteorites and the solar system, and the origin of meteorites. In 1966 the
University of California Board of Regents voted to name UCSD’s first academic building
(formerly “Building B”) “Harold and Frieda Urey Hall” in honor of both Dr. Urey and his
wife Frieda. In 1970 Harold Urey was honored with a newly created title: University
Professor. He became a Professor Emeritus in 1972.
Continuing his efforts on behalf of nuclear arms control, Urey became a member of the
Union of Concerned Scientists, a group with 2,300 members including seven Nobel
laureates. In 1975 the organization petitioned President Gerald Ford to decrease the
production of nuclear power plants. Urey himself was concerned with the safety of nuclear
power and the need for a national plan to dispose of nuclear wastes. He feared that the
global expansion of nuclear generating facilities could cause the spread of nuclear
Urey took an active interest in the United States space program, particularly the Ranger
and Apollo moon missions. He chaired the University of California’s Statewide Advisory
Committee on Space Science from 1959 to 1961. Associated with the National
Aeronautics and Space Administration (NASA), he served as consultant to the Lunar and
Planetary Missions Board and was a member of the Planetology Committee. He personally
analyzed samples of moon rock obtained by the moon missions.
Urey received numerous honors in addition to the Nobel Prize. He was awarded more
than 20 honorary doctorates, over a dozen medals, and was a member or fellow of nearly
30 societies and academies. In 1965 President Lyndon Johnson awarded him the National
Medal of Science. Urey’s bibliography of scientific publications exceeds 200 titles.
Harold Urey died in his La Jolla home in 1981.