paragraph_text: ``Little Boy ''was the codename for the atomic bomb dropped on the Japanese city of Hiroshima on 6 August 1945 during World War II by the Boeing B - 29 Superfortress Enola Gay, piloted by Colonel Paul W. Tibbets, Jr., commander of the 509th Composite Group of the United States Army Air Forces. It was the first atomic bomb to be used in warfare. The Hiroshima bombing was the second artificial nuclear explosion in history, after the Trinity test, and the first uranium - based detonation. It exploded with an energy of approximately 15 kilotons of TNT (63 TJ). The bomb caused significant destruction to the city of Hiroshima and its occupants.

paragraph_text: Heinz Barwich (22 July 1911 in Berlin – 10 April 1966 in Cologne) was a German nuclear physicist. He was deputy director of the Siemens Research Laboratory II in Berlin. At the close of World War II, he followed the decision of Gustav Hertz, to go to the Soviet Union for ten years to work on the Soviet atomic bomb project, for which he received the Stalin Prize. He was director of the "Zentralinstitut für Kernforschung" (Central Institute for Nuclear Research) at Rossendorf near Dresden. For a few years he was director of the Joint Institute for Nuclear Research in Dubna, Russia. In 1964 he defected to the West.

paragraph_text: Atomic bombings of Hiroshima and Nagasaki Part of the Pacific War of World War II Atomic bomb mushroom clouds over Hiroshima (left) and Nagasaki (right) Date August 6 and August 9, 1945 Location Hiroshima and Nagasaki, Empire of Japan Result Allied victory Belligerents United States Manhattan Project: United Kingdom Canada Japan Commanders and leaders William S. Parsons Paul W. Tibbets, Jr. Charles Sweeney Frederick Ashworth Shunroku Hata Units involved Manhattan District: 50 U.S., 2 British 509th Composite Group: 1,770 U.S. Second General Army: Hiroshima: 40,000 (5 Anti-aircraft batteries) Nagasaki: 9,000 (4 Anti-aircraft batteries) Casualties and losses 20 British, Dutch, and American prisoners of war killed Hiroshima: 20,000 soldiers killed 70,000 -- 126,000 civilians killed Nagasaki: 39,000 -- 80,000 killed Total: 129,000 -- 226,000 + killed

paragraph_text: The Hanford Site is a decommissioned nuclear production complex operated by the United States federal government on the Columbia River in Benton County in the U.S. state of Washington. The site has been known by many names, including Hanford Project, Hanford Works, Hanford Engineer Works and Hanford Nuclear Reservation. Established in 1943 as part of the Manhattan Project in Hanford, south-central Washington, the site was home to the B Reactor, the first full-scale plutonium production reactor in the world. Plutonium manufactured at the site was used in the first nuclear bomb, tested at the Trinity site, and in Fat Man, the bomb detonated over Nagasaki, Japan.

paragraph_text: Two major types of atomic bombs were developed by the United States during World War II: a uranium-based device (codenamed "Little Boy") whose fissile material was highly enriched uranium, and a plutonium-based device (see Trinity test and "Fat Man") whose plutonium was derived from uranium-238. The uranium-based Little Boy device became the first nuclear weapon used in war when it was detonated over the Japanese city of Hiroshima on 6 August 1945. Exploding with a yield equivalent to 12,500 tonnes of TNT, the blast and thermal wave of the bomb destroyed nearly 50,000 buildings and killed approximately 75,000 people (see Atomic bombings of Hiroshima and Nagasaki). Initially it was believed that uranium was relatively rare, and that nuclear proliferation could be avoided by simply buying up all known uranium stocks, but within a decade large deposits of it were discovered in many places around the world.

paragraph_text: Richard Phillips Feynman (/ˈfaɪnmən/; May 11, 1918 – February 15, 1988) was an American theoretical physicist known for his work in the path integral formulation of quantum mechanics, the theory of quantum electrodynamics, and the physics of the superfluidity of supercooled liquid helium, as well as in particle physics for which he proposed the parton model. For his contributions to the development of quantum electrodynamics, Feynman, jointly with Julian Schwinger and Sin-Itiro Tomonaga, received the Nobel Prize in Physics in 1965. He developed a widely used pictorial representation scheme for the mathematical expressions governing the behavior of subatomic particles, which later became known as Feynman diagrams. During his lifetime, Feynman became one of the best-known scientists in the world. In a 1999 poll of 130 leading physicists worldwide by the British journal Physics World he was ranked as one of the ten greatest physicists of all time.

paragraph_text: In simple terms, the Cold War could be viewed as an expression of the ideological struggle between communism and capitalism. The United States faced a new uncertainty beginning in September 1949, when it lost its monopoly on the atomic bomb. American intelligence agencies discovered that the Soviet Union had exploded its first atomic bomb, with the consequence that the United States potentially could face a future nuclear war that, for the first time, might devastate its cities. Given this new danger, the United States participated in an arms race with the Soviet Union that included development of the hydrogen bomb, as well as intercontinental strategic bombers and intercontinental ballistic missiles (ICBMs) capable of delivering nuclear weapons. A new fear of communism and its sympathizers swept the United States during the 1950s, which devolved into paranoid McCarthyism. With communism spreading in China, Korea, and Eastern Europe, Americans came to feel so threatened that popular and political culture condoned extensive "witch-hunts" to expose communist spies. Part of the American reaction to the Soviet atomic and hydrogen bomb tests included maintaining a large Air Force, under the control of the Strategic Air Command (SAC). SAC employed intercontinental strategic bombers, as well as medium-bombers based close to Soviet airspace (in western Europe and in Turkey) that were capable of delivering nuclear payloads.

paragraph_text: Feynman's other work at Los Alamos included calculating neutron equations for the Los Alamos "Water Boiler", a small nuclear reactor, to measure how close an assembly of fissile material was to criticality. On completing this work he was transferred to the Oak Ridge facility, where he aided engineers in devising safety procedures for material storage so that criticality accidents (for example, due to sub-critical amounts of fissile material inadvertently stored in proximity on opposite sides of a wall) could be avoided. He also did theoretical work and calculations on the proposed uranium hydride bomb, which later proved not to be feasible.

paragraph_text: At Los Alamos, physicist Robert Serber proposed that instead of relying on spontaneous fission, the chain reaction inside the atomic bomb should be triggered by a neutron initiator. The best - known neutron sources were radium - beryllium and polonium - beryllium. The latter was chosen, as polonium has a 138 - day half - life, which made it intense enough to be useful but not long - lived enough to be stockpiled. Thomas took charge of the development of techniques to industrially refine polonium for use with beryllium in the ``urchin ''internal neutron initiators. This effort became the Dayton Project.

paragraph_text: Feynman was elected a Foreign Member of the Royal Society (ForMemRS) in 1965. At this time in the early 1960s, Feynman exhausted himself by working on multiple major projects at the same time, including a request, while at Caltech, to "spruce up" the teaching of undergraduates. After three years devoted to the task, he produced a series of lectures that eventually became The Feynman Lectures on Physics. He wanted a picture of a drumhead sprinkled with powder to show the modes of vibration at the beginning of the book. Concerned over the connections to drugs and rock and roll that could be made from the image, the publishers changed the cover to plain red, though they included a picture of him playing drums in the foreword. The Feynman Lectures on Physics occupied two physicists, Robert B. Leighton and Matthew Sands, as part-time co-authors for several years. Even though the books were not adopted by most universities as textbooks, they continue to sell well because they provide a deep understanding of physics. Many of his lectures and miscellaneous talks were turned into other books, including The Character of Physical Law, QED: The Strange Theory of Light and Matter, Statistical Mechanics, Lectures on Gravitation, and the Feynman Lectures on Computation.

paragraph_text: Josiah Parsons Cooke (October 12, 1827 – September 3, 1894) was an American scientist who worked at Harvard University and was instrumental in the measurement of atomic weights, inspiring America's first Nobel laureate in chemistry, Theodore Richards, to pursue similar research. Cooke's 1854 paper on atomic weights has been said to foreshadow the periodic law developed later by Mendeleev and others. Historian I. Bernard Cohen described Cooke "as the first university chemist to do truly distinguished work in the field of chemistry" in the United States.

paragraph_text: John Ray Dunning (September 24, 1907 – August 25, 1975) was an American physicist who played key roles in the Manhattan Project that developed the first atomic bombs. He specialized in neutron physics, and did pioneering work in gaseous diffusion for isotope separation. He was Dean of the School of Engineering and Applied Science at Columbia University from 1950 to 1969.

paragraph_text: After the war, Feynman declined an offer from the Institute for Advanced Study in Princeton, New Jersey, despite the presence there of such distinguished faculty members as Albert Einstein, Kurt Gödel and John von Neumann. Feynman followed Hans Bethe, instead, to Cornell University, where Feynman taught theoretical physics from 1945 to 1950. During a temporary depression following the destruction of Hiroshima by the bomb produced by the Manhattan Project, he focused on complex physics problems, not for utility, but for self-satisfaction. One of these was analyzing the physics of a twirling, nutating dish as it is moving through the air. His work during this period, which used equations of rotation to express various spinning speeds, proved important to his Nobel Prize–winning work, yet because he felt burned out and had turned his attention to less immediately practical problems, he was surprised by the offers of professorships from other renowned universities.

paragraph_text: The Manhattan Project was a research and development undertaking during World War II that produced the first nuclear weapons. It was led by the United States with the support of the United Kingdom and Canada. From 1942 to 1946, the project was under the direction of Major General Leslie Groves of the U.S. Army Corps of Engineers. Nuclear physicist Robert Oppenheimer was the director of the Los Alamos Laboratory that designed the actual bombs. The Army component of the project was designated the Manhattan District; ``Manhattan ''gradually superseded the official codename, Development of Substitute Materials, for the entire project. Along the way, the project absorbed its earlier British counterpart, Tube Alloys. The Manhattan Project began modestly in 1939, but grew to employ more than 130,000 people and cost nearly US $2 billion (about $22 billion in 2016 dollars). Over 90% of the cost was for building factories and to produce fissile material, with less than 10% for development and production of the weapons. Research and production took place at more than 30 sites across the United States, the United Kingdom, and Canada.

paragraph_text: In the late 1980s, according to "Richard Feynman and the Connection Machine", Feynman played a crucial role in developing the first massively parallel computer, and in finding innovative uses for it in numerical computations, in building neural networks, as well as physical simulations using cellular automata (such as turbulent fluid flow), working with Stephen Wolfram at Caltech. His son Carl also played a role in the development of the original Connection Machine engineering; Feynman influencing the interconnects while his son worked on the software.

paragraph_text: In atomic physics, Hund's rules refers to a set of rules that German physicist Friedrich Hund formulated around 1927, which are used to determine the term symbol that corresponds to the ground state of a multi-electron atom. The first rule is especially important in chemistry, where it is often referred to simply as Hund's Rule.

paragraph_text: On July 16, 1945, with numerous other Manhattan Project personnel, von Neumann was an eyewitness to the first atomic bomb blast, code named Trinity, conducted as a test of the implosion method device, at the bombing range near Alamogordo Army Airfield, 35 miles (56 km) southeast of Socorro, New Mexico. Based on his observation alone, von Neumann estimated the test had resulted in a blast equivalent to 5 kilotons of TNT (21 TJ) but Enrico Fermi produced a more accurate estimate of 10 kilotons by dropping scraps of torn-up paper as the shock wave passed his location and watching how far they scattered. The actual power of the explosion had been between 20 and 22 kilotons. It was in von Neumann's 1944 papers that the expression "kilotons" appeared for the first time. After the war, Robert Oppenheimer remarked that the physicists involved in the Manhattan project had "known sin". Von Neumann's response was that "sometimes someone confesses a sin in order to take credit for it."

paragraph_text: Due to the top secret nature of the work, Los Alamos was isolated. In Feynman's own words, "There wasn't anything to do there." Bored, he indulged his curiosity by learning to pick the combination locks on cabinets and desks used to secure papers. Feynman played many jokes on colleagues. In one case he found the combination to a locked filing cabinet by trying the numbers he thought a physicist would use (it proved to be 27–18–28 after the base of natural logarithms, e = 2.71828...), and found that the three filing cabinets where a colleague kept a set of atomic bomb research notes all had the same combination. He left a series of notes in the cabinets as a prank, which initially spooked his colleague, Frederic de Hoffmann, into thinking a spy or saboteur had gained access to atomic bomb secrets. On several occasions, Feynman drove to Albuquerque to see his ailing wife in a car borrowed from Klaus Fuchs, who was later discovered to be a real spy for the Soviets, transporting nuclear secrets in his car to Santa Fe.

paragraph_text: Nuclear weapons possess enormous destructive power from nuclear fission or combined fission and fusion reactions. Starting with scientific breakthroughs made during the 1930s, the United States, the United Kingdom and Canada collaborated during World War II in what was called the Manhattan Project to counter the suspected Nazi German atomic bomb project. In August 1945, two fission bombs were dropped on Japan, standing to date as the only use of nuclear weapons in combat. The Soviet Union started development shortly thereafter with their own atomic bomb project, and not long after that both countries developed even more powerful fusion weapons known as ``hydrogen bombs ''.

paragraph_text: The Day After Trinity (a.k.a. The Day After Trinity: J. Robert Oppenheimer and the Atomic Bomb) is a 1980 documentary film directed and produced by Jon H. Else in association with KTEH public television in San Jose, California. The film tells the story of J. Robert Oppenheimer (1904–1967), the theoretical physicist who led the effort to build the first atomic bomb, tested in July 1945 at Trinity site in New Mexico. Featuring candid interviews with several Manhattan Project scientists, as well as newly declassified archival footage, "The Day After Trinity" was nominated for an Academy Award for Best Documentary Feature of 1980, and received a Peabody Award in 1981.

Question: Who was the US physicist who directed the project that developed the first atomic bomb at the same place where Feynman worked on Water Boiler?
Answer: Robert Oppenheimer