Biographical Memoirs Volume 68 (1995) / Chapter Skim
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Harold Clayton Urey
Harold Clayton Urey
Pages 363-412
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From page 363... ...
Although he was meticulous in his attention to cletail, his sights were always on broad questions at the forefront of knowlecige. His unusual powers of concentration and capacity for hard work accounted for much of his success in exploring en cl opening up major new fields of research, including his discovery of deuterium and work on isotope chemistry, isotope separation, isotope geology, en cl cosmochemistry.
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From page 364... ...
to the sense of urgency that developed in the Manhattan Project late in 1941. His major contributions and cleclication to the success of the program through his work on uranium isotope separation, heavy water production, anc!
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From page 365... ...
have prepared this memoir alone. UREY'S EARLY LIFE UP TO HIS ENTRANCE TO GRADUATE SCHOOL IN BERKELEY Harold Clayton Urey was born in Walkerton, a small town in Indiana, on April 29, IS93.
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From page 366... ...
Many years later in his Willard Gibbs Medal adclress he spoke warmly of the inspiration he receivect from the professors at the University of Montana en c! of the beginning of his interest in science due to their counseling advice, in particular the influence of A
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From page 367... ...
l he second part of his thesis was of lesser long-term significance. He attempted to calculate the heat capacities and entropies of polyatomic gases before the correct description of the rotational energy states of molecules had been established by quantum mechanics.
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From page 368... ...
He received a fellowship from the American Scandinavian Foundation and went to the Institute of Theoretical Physics, Bohr Institute, in Copenhagen. The institute under Bohr's leadership was a major center in theoretical physics, particularly the (levelopment of the new quantum mechanics and its application to atomic ant!
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From page 369... ...
Their natural abundances are 0.04 and 0.2 percent, respectively. The chemical atomic weight scale was based on the assumption that oxygen had only one isotope, mass 16.
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From page 370... ...
70 and ~80 was 1.00756. To reconcile the physical and chemical atomic weights of hydrogen, Birge and Menze} postulated the existence of a stable isotope of hydrogen of mass 2 with a natural abundance of ~ :4500.
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During the period when Brickwedde was preparing the enriched sample, Urey and Murphy determined the optimum conditions for excitation of the atomic spectrum of hydrogen and suppression of the molecular spectrum. They did in fact find the lines to be expected for 2H in the atomic spectrum of natural hydrogen.
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From page 372... ...
This value, if correct, wouIcl have brought the physical and chemical atomic weights of hydrogen into exact agreement and invaliciatec! the basis of Birge ant!
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THERMODYNAMIC PROPERTIES OF ISOTOPIC SUBSTANCES Urey's Nobel address was titled "Some Thermodynamic Properties of Hydrogen and Deuterium." The first part covered the discovery of deuterium. Two-thirds of the address dealt with the differences in the thermodynamic properties of isotopes and the feasibility of isotope separation based on these differences.
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From page 374... ...
Reflux was achieved by cheap reagents acids and alkali. Compared with other isotope separation processes, centrifuges, and diffusion, the chemical exchange process and the relatect liquic3-vapor clistilIation have large throughput per unit volume of separating equipment.
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ISOTOPES AS TRACERS Enriched stable isotopes of H
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From page 376... ...
percent in the ~8o/~6O ratio at the natural abundance level, which is 0.2 percent. Nier and Thode had each clevelopec!
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The possible need for separating the uranium isotopes was obvious. As the recognized florid leacler in isotope separation, Urey's main potential contribution to fission research was clearly in that
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From page 378... ...
, throw light on the status of isotope separation at that time and on Urey's speculations about methods for separating isotopes of the heavy elements. He proposed a countercurrent flow centrifuge, designee to attain a number of stages of separation in a single machine, thus reducing the number of machines required in a cascade and the amount of material circulated between machines.
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From page 379... ...
experimental centrifuge studies at the University of Virginia; gaseous diffusion separation research at Harvard; and thermal diffusion, chemical separation, and centrifugal fractionation at Columbia. Urey undertook personal direction of research on chemical separation of the uranium isotopes and on separation by the countercurrent centrifuge.
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From page 380... ...
A new Office of Scientific Research and Development was createcl in the Executive Office of the President as the center for the application of science to national defense, and Urey was a member of its Section on Uranium. He was given responsibility for uranium isotope separation by exchange methods and for heavy water production.
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From page 381... ...
It is an irony of history that subsequent experiments in 1943 and 1944 proved that countercurrent machines could operate close to theoretical efficiency. At least six nations have at the present time operated countercurrent centrifuges with UFO, and it is the uranium isotope separation method of choice for five of them.
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A new process was devised for producing heavy water, baser! on clualtemperature exchange between hydrogen sulficle anct water.
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He renewed his efforts to realize a homogeneous heavy water uranium slurry reactor, proposed by Halban, for plutonium procluction. This led to the research piles in Chicago ant!
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Craig en cl Urey (1953,1) recIassifiecl the meteorites using chemical criteria anc!
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He began to look for experimental areas beyond the i~o/~60 system where his mass spectrometric skills coulcl be appliecl. A young graduate student named Jerry Wasserburg turned up at Chicago, and Urey put him to work on the 40K/40Ar isotopic (rating system.
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Not long after this a graduate student named Stanley Miller presented himself to Urey ant! proposed to do an experimental thesis testing this hypothesis in the laboratory.
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Urey was very active at the time of Apollo 11, when the first lunar samples were returned and the first ciata were appearing. Though he (unfortunately)
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He'cl thank the group warmly, again apologize, and rush out. The effect of this display on young graduate students was remarkable.
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As WorIcl War IT enclecI, Urey, then at the University of Chicago, became concerned and worrier! about the potential of atomic bombs, in whose creation he had played such an important role.
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At this time, when many were worried about how to keep the "secret" of the atomic bomb and how to prevent dominance by the Soviet Union, he wrote, "The real problem that faces this country is a long-term one. It is a problem of the proper education and inspiration of our youth." He approached with great zest the teaching not only of graduate students but also of first-year unclergracluate chemistry courses.
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From page 391... ...
. At the time Heroin was notified of the award of the Nobel Prize, Frieda was expecting their thirc!
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From page 392... ...
Urey may be considered to have establishecI at least four fielcis of scientific research: stable isotope chemistry, including isotope geochemistry, geochronology, and isotope separation; paleotemperature measurement; cosmochemistry; and the origin of terrestrial life. The scope of his interests ant!
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FI A R O L D C LAYT O N U R E Y 393 cat Memoirs of the Royal Society of London, speaking of Harold as "the founder of the field of cosmochemistry" wrote, "Urey, uncloubtedly, was the first who rigorously defined this field by its problems and by asking precise questions." His ideas concerning the primordial atmosphere and the beginning of life on earth opened up a completely new approach to the study of the origin of life on this planet. Urey's vigorous ant]
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From page 394... ...
1emlstry University of California, Berkeley, 1921-23, Ph.D. in chemistry with a minor in physics American-Scandinavian Foundation Fellow, Niels Bohr Institute for Theoretical Physics, Copenhagen, 1923-24 PROFESSIONAL EMPLOYMENT 1911-14 Teacher in rural schools in Indiana, 1911-12; Montana, 1912-14 1918-19 Barrett Chemical Co., Baltimore, research chemist 1919-21 University of Montana, instructor in chemistry 1924-29 Johns Hopkins University, associate in chemistry 1929-36 Columbia University, associate professor of chemistry, 1929-34; Ernest Kempton Adams Fellow, 1933-36; professor of chemistry, 1934-45; executive officer, Department of Chemistry, 1939-42; director of war research, SAM Laboratories, 1940-45 1933-40 Journal of Chemical Physics, editor 1945-58 University of Chicago, Institute for Nuclear Studies: Distinguished Service Professor of Chemistry, 1945-52; Martin A
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Truman 1950 Distinguished Service Award, Phi Beta Kappa Centennial Award, Northwestern University 1957 Jesuit Centennial Citation, Chicago 1960 Silver Medal, Research Institute of America Cordoza Award, Tau Epsilon Rho Law Fraternity 1961 Alexander Hamilton Award, Columbia University 1962 l. Lawrence Smith Medal, National Academy of Sciences 1963 Remsen Memorial Award, American Chemical Society, Baltimore Section 1964 University of Paris Medal National Medal of Science 1966 Gold Medal, Royal Astronomy Society, London American Academy of Achievement Award, Golden Plate Award 395 1967 Man of Distinction Award, Women's Guild of Temple Emanu-El, San Diego 1969 Chemical Pioneer Award, American Institute of Chemists Arthur L
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M Goldschmidt Medal, Geochemical Society 1976 NASA Group Achievement Award, U.S.
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American Academy of Arts and Sciences American Association for the Advancement of Science American Association of University Professors American Astronomical Society American Astronautical Society (fellow) American Chemical Society American Geophysical Union (honorary fellow)
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398 BIOGRAPHICAL MEMOIRS Weizmann Institute of Science (honorary fellow) World Academy of Arts and Sciences, American Division (corresponding member)
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I The effect of black-body radiation on a molecular beam of nitrogen pentoxide.
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The relative abundance of hydrogen isotopes in natural hydrogen.
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From page 401... ...
The relative abundance of the nitrogen and oxygen isotopes.
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Teal. The hydrogen isotope of atomic weight two.
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In Recent Advances in Surface Chemistry and Chemical Physics, pp.
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22:82-91. 1947 The thermodynamic properties of isotopic substances.
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Acta 1:209-77. The social implications of the atomic bomb.
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From page 406... ...
In Science in Space, a report by the Space Science Board, National Academy of Sciences, pp.
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From page 407... ...
The origin and evolution of the solar system. In Space Science, ed.
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1966 Chemical evidence relative to the origin of the solar system.
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Young. Organic compounds in lunar samples: pyrolysis products, hydrocarbons, amino acids.
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Carbon compounds in pyrolysates and amino acids in extracts of Apollo 14 lunar samples.
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FI A R O L D C LAYT O N U R E Y 411 With H Alfven.
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