In 1931, the American physical chemist Harold Urey demonstrated the existence of what type of 'weighty' liquid that proved important in the development of the atomic bomb?
"the development of an atomic bomb a theoretical possibility. Fears that a German atomic bomb project would develop atomic weapons first, especially among scientists who were refugees from Nazi Germany and other fascist countries, were expressed in the Einstein-Szilard letter. This prompted preliminary research in the United States in late 1939. Progress was slow until the arrival of the British MAUD Committee report in late 1941, which indicated that only 5 to 10 kilograms of isotopically enriched uranium-235 were needed for a bomb instead of tons of natural uranium and a neutron moderator like heavy water. The 1943 Quebec Agreement"
"a chemical method, but it would rapidly transform into a dynamic mixture of 25% light water, 25% heavy water, and 50% semi-heavy water. However, if it were made in the gas phase and directly deposited into a solid, semi heavy water in the form of ice could be stable. This is due to collisions between water vapour molecules being almost completely negligible in the gas phase at standard temperatures, and once crystallized, collisions between the molecules cease altogether due to the rigid lattice structure of solid ice. Harold Urey discovered the isotope deuterium in 1931 and was later able to"
"Harold Urey Harold Clayton Urey (April 29, 1893 – January 5, 1981) was an American physical chemist whose pioneering work on isotopes earned him the Nobel Prize in Chemistry in 1934 for the discovery of deuterium. He played a significant role in the development of the atom bomb, as well as contributing to theories on the development of organic life from non-living matter. Born in Walkerton, Indiana, Urey studied thermodynamics under Gilbert N. Lewis at the University of California. After he received his PhD in 1923, he was awarded a fellowship by the American-Scandinavian Foundation to study at the Niels"
"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. Harold Urey Harold Clayton Urey (April 29, 1893 – January 5, 1981) was an American physical chemist whose pioneering work on isotopes earned him the Nobel Prize in Chemistry in 1934 for the discovery of deuterium. He played a significant role in the development of the atom bomb, as well as contributing to theories on the development of organic life from non-living matter. Born in Walkerton,"
"obtained the help of Ferdinand Brickwedde, whom Urey had known at Johns Hopkins. The first sample that Brickwedde sent was evaporated at at a pressure of . To their surprise, this showed no evidence of enrichment. Brickwedde then prepared a second sample evaporated at at a pressure of . On this sample, the Balmer lines for heavy hydrogen were seven times as intense. The paper announcing the discovery of what we now call 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""."
"the two methods, they predicted that only one hydrogen atom in 4,500 was of the heavy isotope. 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 . Urey had access to a 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"
"with a measured average atomic mass very close to , the known mass of the proton, always has a nucleus composed of a single proton (a known particle), and could not contain a second proton. Thus, hydrogen could have no heavy isotopes. It was first detected spectroscopically in late 1931 by Harold Urey, a chemist at Columbia University. Urey's collaborator, Ferdinand Brickwedde, distilled five liters of cryogenically produced liquid hydrogen to of liquid, using the low-temperature physics laboratory that had recently been established at the National Bureau of Standards in Washington, D.C. (now the National Institute of Standards and Technology)."
"in 1931 by Urey, who received the 1934 Nobel Prize in Chemistry for this work. Urey was able to supply them with both heavy water and gaseous deuterium for their experiments. Despite its simplicity, Stern's group in Hamburg had observed that hydrogen did not behave as predicted. Urey also helped in another way; he gave Rabi half his prize money to fund the Molecular Beam Laboratory. Other scientists whose careers began at the Molecular Beam Laboratory included Norman Ramsey, Julian Schwinger, Jerome Kellogg and Polykarp Kusch. All were men; Rabi did not believe that women could be physicists. He never"
"in 1932 of heavy hydrogen (deuterium) by Harold C Urey. Giauque was awarded the 1949 Nobel Prize for chemistry for this work, and did not forget to recognize Johnston's contribution. Johnston was appointed assistant professor at Ohio State University in 1929 with plans to create a cryogenics laboratory to rival that at Berkeley, but sufficient funds were not available until 1939, boosted by federal money earmarked for war-related research, notably the Manhattan Project, for which he was a director from 1942-46. A new building (titled War Research Building) was completed around the end of 1942 and the first liquid hydrogen"
"produced by the P-9 Project: Chicago Pile 3 at Argonne, and ZEEP and NRX at the Chalk River Laboratories in Canada. Heavy water is a form of water that contains a larger than normal amount of the hydrogen isotope deuterium, also known as heavy hydrogen, rather than the common hydrogen-1 isotope that makes up most of the hydrogen in ordinary water. Deuterium was discovered by Harold Urey in 1931 and he was later able to concentrate it in water. His mentor Gilbert Newton Lewis isolated the first sample of pure heavy water by electrolysis in 1933. Although a scientific curiosity"
"Uranium hydride bomb The uranium hydride bomb was a variant design of the atomic bomb first suggested by Robert Oppenheimer in 1939 and advocated and tested by Edward Teller. It used deuterium, an isotope of hydrogen, as a neutron moderator in a uranium-deuterium ceramic compact. Unlike all other fission-based weapon types, the concept relies on a chain reaction of slow nuclear fission (see neutron temperature). Bomb efficiency was adversely affected by the cooling of neutrons since the latter delays the reaction, as delineated by Rob Serber in his 1992 extension of the original Los Alamos Primer. The term hydride for"
"experiment was performed by scientist Stanley Miller under the guidance of Harold Urey in the early 1950s. In the Miller–Urey experiment, water was boiled in a flask with the gases hydrogen, ammonia, and methane. The gases flowed through the apparatus past two electrodes that produced an electrical charge that acted as the lightning that would have been in the atmosphere before life on Earth. When the gases condensed after being cooled down, they fell back into the boiling flask. What Stanley Miller found in the flask when he observed the water were acids and amino acids. Amino acids are the"
"of this study, which helped formalize modern chemical thermodynamics. Lewis was the first to produce a pure sample of deuterium oxide (heavy water) in 1933 and the first to study survival and growth of life forms in heavy water. By accelerating deuterons (deuterium nuclei) in Ernest O. Lawrence's cyclotron, he was able to study many of the properties of atomic nuclei. During the 1930s, he was mentor to Glenn T. Seaborg, who was retained for post-doctoral work as Lewis' personal research assistant. Seaborg went on to win the 1951 Nobel Prize in Chemistry and have the element seaborgium named in"
"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"
"spectroscopic lines for publishable data, Murphy and Urey paired with Ferdinand Brickwedde and distilled a more concentrated pool of heavy hydrogen, known today as deuterium. This work on hydrogen isotopes won Urey the 1934 Nobel Prize in Chemistry. Also in 1934, scientists Ernest Rutherford, Mark Oliphant, and Paul Harteck, produced the radioactive isotope tritium by hitting deuterium with high energy nuclei. The deuterium used in the experiment was a generous gift of heavy water from the Berkeley physicist Gilbert N Lewis. Bombarding deuterium produced two previously undetected isotopes, helium-3 and hydrogen-3. Rutherford and his colleagues successfully created tritium, but incorrectly"
"Harold Urey had a meeting at the American Physical Society in Washington, D.C. At the time, the prospect of building an atomic bomb seemed dim, and even creating a chain reaction would likely require enriched uranium. They therefore recommended that research be conducted with the aim of developing the means to separate kilogram amounts of uranium-235. At a lunch on 21 May 1940, George B. Kistiakowsky suggested the possibility of using gaseous diffusion. Gaseous diffusion is based on Graham's law, which states that the rate of effusion of a gas through a porous barrier is inversely proportional to the square"
"(uranium) and Thin Man (plutonium), and the Fat Man plutonium implosion bomb. In early 1943 Oppenheimer determined that two projects should proceed forwards: the Thin Man project (plutonium gun) and the Fat Man project (plutonium implosion). The plutonium gun was to receive the bulk of the research effort, as it was the project with the most uncertainty involved. It was assumed that the uranium gun-type bomb could then be adapted from it. In December 1943 the British mission of 19 scientists arrived in Los Alamos. Hans Bethe became head of the Theoretical Division. In April 1944 it was found by"
"an atomic bomb. Upon returning home, Penney directed Britain's own nuclear weapons directorate, codename ""Tube Alloys"", and directed scientific research at the Atomic Energy Research Establishment which resulted in the first detonation of a British nuclear bomb, (codename ""Operation Hurricane"") in 1952. After the test, Penney became chief adviser to the newly created British government's United Kingdom Atomic Energy Authority (UKAEA). He was later chairman of the authority, which he used in international negotiations to control nuclear testing with the Partial Nuclear Test Ban Treaty. Penney's notable scientific contributions included the mathematics for complex wave dynamics, both in shock and"
"United Kingdom and the United States agreed to develop the ""Tube Alloys"" Project and created a committee to manage the project which included C. D. Howe, the Canadian Minister of Munitions and Supply. This was the code name for the British Uranium Committee project which had worked on a theoretical design for an atomic bomb. One significant contribution was a calculation of the critical mass of uranium. The mass was less than earlier estimates and suggested that development of a fission bomb was practical. ""Tube Alloys"" was part of a shipment of the most secret scientific research in Great Britain"
"1953. A graduate student, Stanley Miller, and his professor, Harold Urey, performed an experiment that demonstrated how organic molecules could have spontaneously formed from inorganic precursors, under conditions like those posited by the Oparin-Haldane Hypothesis. The now-famous ""Miller–Urey experiment"" used a highly reduced mixture of gases—methane, ammonia and hydrogen—to form basic organic monomers, such as amino acids. This provided direct experimental support for the second point of the ""soup"" theory, and it is around the remaining two points of the theory that much of the debate now centers. Apart from the Miller–Urey experiment, the next most important step in research"
"(then, like Ashkin, a Columbia graduate student), John R. Dunning (an associate professor at Columbia who had built a small cyclotron in the mid-1930s), Walter Zinn (a Columbia professor who worked with the Columbia cyclotron to demonstrate the possibility of a sustained chain reaction), George B. Pegram (Dean of Columbia's Faculties of Political Science, Philosophy, and Pure Science, who helped bring Fermi to the United States and brought him together with representatives of the U.S. Navy Department for the first discussion of the atomic bomb) and Harold Urey (associate professor of Chemistry whose work on separation of isotopes resulted in"
"concluded that a uranium-235 bomb could be feasible in as little as two years using of uranium-235 with a yield equivalent to ; the second concluded that the controlled fission be a source of energy for powering machines and a source of radio-isotopes. As a result of the MAUD Committee report, the British started an atomic bomb program under the codename Tube Alloys. Urey began considering isotope separation methods. The centrifuge process was regarded as the most promising. Beams had developed such a process at the University of Virginia during the 1930s, but had encountered technical difficulties. The process required"
"concentrate it in water. Urey's mentor Gilbert Newton Lewis isolated the first sample of pure heavy water by electrolysis in 1933. George de Hevesy and Erich Hofer used heavy water in 1934 in one of the first biological tracer experiments, to estimate the rate of turnover of water in the human body. The history of large-quantity production and use of heavy water in early nuclear experiments is given below. Emilian Bratu and Otto Redlich studied the autodissociation of heavy water in 1934. Different isotopes of chemical elements have slightly different chemical behaviors, but for most elements the differences are far"
"slightly from one kind of natural water to another (see Vienna Standard Mean Ocean Water). The deuterium isotope's name is formed from the Greek ""deuteros"", meaning ""second"", to denote the two particles composing the nucleus. Deuterium was discovered and named in 1931 by Harold Urey. When the neutron was discovered in 1932, this made the nuclear structure of deuterium obvious, and Urey won the Nobel Prize in 1934. Soon after deuterium's discovery, Urey and others produced samples of ""heavy water"" in which the deuterium content had been highly concentrated. Deuterium is destroyed in the interiors of stars faster than it"
"result is cell dysfunction and death. Heavy water was first produced in 1932, a few months after the discovery of deuterium. With the discovery of nuclear fission in late 1938, and the need for a neutron moderator that captured few neutrons, heavy water became a component of early nuclear energy research. Since then, heavy water has been an essential component in some types of reactors, both those that generate power and those designed to produce isotopes for nuclear weapons. These heavy water reactors have the advantage of being able to run on natural uranium without using graphite moderators that pose"
"such as Ernest Rutherford, wanted the isotope to be called ""diplogen"", from the Greek diploos (double), and the nucleus to be called diplon. The amount inferred for normal abundance of this heavy isotope of hydrogen was so small (only about 1 atom in 6400 hydrogen atoms in ocean water (156 deuteriums per million hydrogens)) that it had not noticeably affected previous measurements of (average) hydrogen atomic mass. This explained why it hadn't been experimentally suspected before. Urey was able to concentrate water to show partial enrichment of deuterium. Lewis had prepared the first samples of pure heavy water in 1933."
"produced displayed a higher density than regular water. Heavy water has a higher freezing point, higher boiling point, and lower refractive index than regular water. Heavy water differs from regular water in that the two atoms of hydrogen have been substituted with two atoms of deuterium, which is an isotope of hydrogen. The mass of heavy water is about 10% more than that of regular water due to the extra neutron in deuterium. Heavy water was discovered by Gilbert N. Lewis in 1933. In 1934, Frandsen, along with Washburn and Smith, also published ""On Change in Density, Index of Refraction,"
"more powerful fusion weapons known as ""hydrogen bombs"". In the first decades of the 20th century, physics was revolutionised with developments in the understanding of the nature of atoms. In 1898, Pierre and Marie Curie discovered that pitchblende, an ore of uranium, contained a substance—which they named radium—that emitted large amounts of radioactivity. Ernest Rutherford and Frederick Soddy identified that atoms were breaking down and turning into different elements. Hopes were raised among scientists and laymen that the elements around us could contain tremendous amounts of unseen energy, waiting to be harnessed. H. G. Wells was inspired to write about"
"bomb. The tests with uranium hydride and uranium deuteride during Operation Upshot–Knothole were disappointing, however. During the early phases of the Manhattan Project, in 1943, uranium hydride was investigated as a promising bomb material; however, it was abandoned by the spring of 1944 as it turned out that such a design would be inefficient. Hydrogen, deuterium, and tritium can be purified by reacting with uranium, then thermally decomposing the resulting hydride/deuteride/tritide. Extremely pure hydrogen has been prepared from beds of uranium hydride for decades. Heating uranium hydride is a convenient way to introduce hydrogen into a vacuum system. The swelling"
"naturally-occurring, non-radioactive, stable isotope of hydrogen. Deuterium was discovered by Harold Urey in 1931, for which he received the Nobel Prize in 1934. The deuterium isotope effect has become an important tool in the elucidation the mechanism of chemical reactions. Deuterium contains one proton, one electron, and a neutron, effectively doubling the mass of the deuterium isotope without changing the its significantly. However, the C-D bond is a bit shorter, and it has reduced electronic polarizability and less hyperconjugative stabilization of adjacent bonds (including the developing anti-bonding orbital of a newly-forming bond). It potentially can result in weaker van der"
"hydrogen bomb, which was first tested in November 1952, only one month after Operation Hurricane. Britain would go on to develop its own hydrogen bombs, which it first tested in 1957. A year later, the United States and Britain resumed nuclear weapons cooperation. The neutron was discovered by James Chadwick at the Cavendish Laboratory at the University of Cambridge in February 1932. In April 1932, his Cavendish colleagues John Cockcroft and Ernest Walton split lithium atoms with accelerated protons. Enrico Fermi and his team in Rome conducted experiments involving the bombardment of elements by slow neutrons, which produced heavier elements"
"his honor while he was still alive. In 1921, Lewis was the first to propose an empirical equation describing the failure of strong electrolytes to obey the law of mass action, a problem that had perplexed physical chemists for twenty years. His empirical equations for what he called ionic strength were later confirmed to be in accord with the Debye–Hückel equation for strong electrolytes, published in 1923. In 1924, by studying the magnetic properties of solutions of oxygen in liquid nitrogen, he found that O molecules were formed. This was the first evidence for tetratomic oxygen. In 1926, he coined"
"the features, science and idea behind the American Fat Man implosion-type nuclear weapon. He broke down the development tasks required to replicate it, identifying outstanding questions that required further research on nuclear weapons. On 3 October 1952, under the code-name ""Operation Hurricane"", the first British nuclear device was successfully detonated in the Monte Bello Islands off the west coast of Australia. The Sputnik crisis and the development of the British hydrogen bomb led to the Atomic Energy Act being amended in 1958, and to a resumption of the nuclear Special Relationship between America and Britain under the 1958 US–UK Mutual"