Harold Urey
Harold Urey

Celebrity Profile

Name: Harold Urey
Occupation: Chemist
Gender: Male
Birth Day: April 29, 1893
Death Date: Jan 5, 1981 (age 87)
Age: Aged 87
Country: United States
Zodiac Sign: Taurus

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Height: in centimeters - N/A
Weight: in kg - N/A
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Harold Urey

Harold Urey was born on April 29, 1893 in United States (87 years old). Harold Urey is a Chemist, zodiac sign: Taurus. Find out Harold Ureynet worth 2020, salary 2020 detail bellow.


He was awarded the Medal of Merit for working on the Manhattan project.

Does Harold Urey Dead or Alive?

As per our current Database, Harold Urey died on Jan 5, 1981 (age 87).

Net Worth

Net Worth 2020


Salary 2020

Not known

Before Fame

He went to an Amish grade school in Indiana as a boy.

Biography Timeline


Harold Clayton Urey was born on April 29, 1893, in Walkerton, Indiana, the son of Samuel Clayton Urey, a school teacher and a minister in the Church of the Brethren, and his wife Cora Rebecca née Reinoehl. He had a younger brother, Clarence, and a younger sister, Martha. The family moved to Glendora, California after Samuel became seriously ill with tuberculosis, in hopes that the climate would improve his health. When it became clear that he would die, the family moved back to Indiana to live with Cora's widowed mother. Samuel died when Harold Urey was six years old.


Urey was educated in an Amish grade school, from which he graduated at the age of 14. He then attended high school in Kendallville, Indiana. After graduating in 1911, he obtained a teacher's certificate from Earlham College, and taught in a small school house in Indiana. He later moved to Montana, where his mother was then living, and he continued to teach there.


Urey entered the University of Montana in Missoula in the autumn of 1914. Unlike Eastern universities of the time, the University of Montana was co-educational in both students and teachers. There Urey earned a Bachelor of Science (BS) degree in zoology in 1917.


An academic career required a doctorate, so in 1921 Urey enrolled in a PhD program at the University of California, Berkeley, where he studied thermodynamics under Gilbert N. Lewis. His initial attempt at a thesis was on the ionization of cesium vapor. He ran into difficulties, and Meghnad Saha published a better paper on the same subject. Urey then wrote his thesis on the ionization states of an ideal gas, which was subsequently published in the Astrophysical Journal. After he received his PhD in 1923, Urey was awarded a fellowship by the American-Scandinavian Foundation to study at the Niels Bohr Institute in Copenhagen, where he met Werner Heisenberg, Hans Kramers, Wolfgang Pauli, Georg von Hevesy, and John Slater. At the conclusion of his stay, he traveled to Germany, where he met Albert Einstein and James Franck.


On returning to the United States, Urey received an offer of a National Research Council fellowship to Harvard University, and also received an offer to be a research associate at Johns Hopkins University. He chose the latter. Before taking up the job, he traveled to Seattle, Washington, to visit his mother. On the way, he stopped by Everett, Washington, where he knew a woman called Kate Daum. Kate introduced Urey to her sister, Frieda. Urey and Frieda soon became engaged. They were married at her father's house in Lawrence, Kansas, in 1926. The couple had four children: Gertrude Bessie (Elisabeth), born in 1927; Frieda Rebecca, born in 1929; Mary Alice, born in 1934; and John Clayton Urey, born in 1939.


At Johns Hopkins, Urey and Arthur Ruark wrote Atoms, Quanta and Molecules (1930), one of the first English texts on quantum mechanics and its applications to atomic and molecular systems. In 1929, Urey became an associate professor of Chemistry at Columbia University, where his colleagues included Rudolph Schoenheimer, David Rittenberg, and T. I. Taylor.


In 1931, Urey set out to find it. Urey and George Murphy calculated from the Balmer series that the heavy isotope should have lines redshifted by 1.1 to 1.8 ångströms (1.1×10 to 1.8×10 metres). Urey had access to a 21-foot (6.4 m) grating spectrograph, a sensitive device that had been recently installed at Columbia and was capable of resolving the Balmer series. With a resolution of 1 Å per millimetre, the machine should have produced a difference of about 1 millimetre. However, since only one atom in 4,500 was heavy, the line on the spectrograph was very faint. Urey therefore decided to delay publishing their results until he had more conclusive evidence that it was heavy hydrogen.


The first sample that Brickwedde sent was evaporated at 20 K (−253.2 °C; −423.7 °F) at a pressure of 1 standard atmosphere (100 kPa). To their surprise, this showed no evidence of enrichment. Brickwedde then prepared a second sample evaporated at 14 K (−259.1 °C; −434.5 °F) at a pressure of 53 mmHg (7.1 kPa). On this sample, the Balmer lines for heavy hydrogen were seven times as intense. The paper announcing the discovery of heavy hydrogen, later named deuterium, was jointly published by Urey, Murphy, and Brickwedde in 1932. Urey was awarded the Nobel Prize in Chemistry in 1934 "for his discovery of heavy hydrogen". He declined to attend the ceremony in Stockholm, so that he could be present at the birth of his daughter Mary Alice.


Urey and Washburn attempted to use electrolysis to create pure heavy water. Their technique was sound, but they were beaten to it in 1933 by Lewis, who had the resources of the University of California at his disposal. Using the Born–Oppenheimer approximation, Urey and David Rittenberg calculated the properties of gases containing hydrogen and deuterium. They extended this to enriching compounds of carbon, nitrogen, and oxygen. These could be used as tracers in biochemistry, resulting in a whole new way of examining chemical reactions. He founded the Journal of Chemical Physics in 1932, and was its first editor, serving in that capacity until 1940.


By the time World War II broke out in Europe in 1939, Urey was recognized as a world expert on isotope separation. Thus far, separation had involved only the light elements. In 1939 and 1940, Urey published two papers on the separation of heavier isotopes in which he proposed centrifugal separation. This assumed great importance due to speculation by Niels Bohr that uranium 235 was fissile. Because it was considered "very doubtful whether a chain reaction can be established without separating 235 from the rest of the uranium," Urey began intensive studies of how uranium enrichment might be achieved. Apart from centrifugal separation, George Kistiakowsky suggested that gaseous diffusion might be a possible method. A third possibility was thermal diffusion. Urey coordinated all isotope separation research efforts, including the effort to produce heavy water, which could be used as a neutron moderator in nuclear reactors.


In May 1941, Urey was appointed to the Committee on Uranium, which oversaw the uranium project as part of the National Defense Research Committee (NDRC). In 1941, Urey and George B. Pegram led a diplomatic mission to England to establish co-operation on development of the atomic bomb. The British were optimistic about gaseous diffusion, but it was clear that both gaseous and centrifugal methods faced formidable technical obstacles. In May 1943, as the Manhattan Project gained momentum. Urey became head of the wartime Substitute Alloy Materials Laboratories (SAM Laboratories) at Columbia, which was responsible for the heavy water and all the isotope enrichment processes except Ernest Lawrence's electromagnetic process.


Apart from his Nobel Prize, he also won the Franklin Medal in 1943, the J. Lawrence Smith Medal in 1962, the Gold Medal of the Royal Astronomical Society in 1966, the Golden Plate Award of the American Academy of Achievement in 1966, and the Priestley Medal of the American Chemical Society in 1973. In 1964 he received the National Medal of Science. He became a Fellow of the Royal Society in 1947. Named after him are lunar impact crater Urey, asteroid 4716 Urey, and the H. C. Urey Prize, awarded for achievement in planetary sciences by the American Astronomical Society. The Harold C. Urey Middle School in Walkerton, Indiana, is also named for him, as is Urey Hall, the chemistry building at Revelle College, UCSD, in La Jolla. UCSD has also established a Harold C. Urey chair whose first holder is Jim Arnold.


The gaseous diffusion process remained more encouraging, although it too had technical obstacles to overcome. By the end of 1943, Urey had over 700 people working for him on gaseous diffusion. The process involved hundreds of cascades, in which corrosive uranium hexafluoride diffused through gaseous barriers, becoming progressively more enriched at every stage. A major problem was finding proper seals for the pumps, but by far the greatest difficulty lay in constructing an appropriate diffusion barrier. Construction of the huge K-25 gaseous diffusion plant was well under way before a suitable barrier became available in quantity in 1944. As a backup, Urey championed thermal diffusion.


Worn out by the effort, Urey left the project in February 1945, handing over his responsibilities to R. H. Crist. The K-25 plant commenced operation in March 1945, and as the bugs were worked out, the plant operated with remarkable efficiency and economy. For a time, uranium was fed into the S50 liquid thermal diffusion plant, then the K-25 gaseous, and finally the Y-12 electromagnetic separation plant; but soon after the war ended the thermal and electromagnetic separation plants were closed down, and separation was performed by K-25 alone. Along with its twin, K-27, constructed in 1946, it became the principal isotope separation plant in the early post-war period. For his work on the Manhattan Project, Urey was awarded the Medal for Merit by the Project director, Major General Leslie R. Groves, Jr.


After the war, Urey became professor of chemistry at the Institute for Nuclear Studies, and then became Ryerson professor of chemistry at the University of Chicago in 1952. He did not continue his pre-war research with isotopes. However, applying the knowledge gained with hydrogen to oxygen, he realized that the fractionation between carbonate and water for oxygen-18 and oxygen-16 would decrease by a factor of 1.04 between 0 and 25 °C (32 and 77 °F). The ratio of the isotopes could then be used to determine average temperatures, assuming that the measurement equipment was sufficiently sensitive. The team included his colleague Ralph Buchsbaum. Examination of a 100-million-year-old belemnite then indicated the summer and winter temperatures that it had lived through over a period of four years. For this pioneering paleoclimatic research, Urey was awarded the Arthur L. Day Medal by the Geological Society of America, and the Goldschmidt Medal of the Geochemical Society.


Urey spent a year in the United Kingdom as a visiting professor at Oxford University in 1956 and 1957. In 1958, he reached the University of Chicago's retirement age of 65, but he accepted a post as a professor at large at the new University of California, San Diego (UCSD), and moved to La Jolla, California. He was subsequently made a professor emeritus there from 1970 to 1981. Urey helped build up the science faculty there. He was one of the founding members of UCSD's school of chemistry, which was created in 1960, along with Stanley Miller, Hans Suess, and Jim Arnold.

Family Life

Harold had four children with his wife Frieda Daum who he married in 1926.

🎂 Upcoming Birthday

Currently, Harold Urey is 128 years, 1 months and 15 days old. Harold Urey will celebrate 129th birthday on a Friday 29th of April 2022. Below we countdown to Harold Urey upcoming birthday.


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