Arthur Compton

For more information on Arthur Holly Compton, visit Britannica.com.

American physicist (1892–1962)

Compton came from a distinguished intellectual family in Wooster, Ohio. His father, Elias, was a professor of philosophy at Wooster College while his brother, Karl, also a physicist, became president of the Massachusetts Institute of Technology. He was educated at Wooster College and at Princeton, where he obtained his PhD in 1916. He began his career by teaching at the University of Minnesota and, after two years with the Westinghouse Corporation in Pittsburgh, he returned to academic life when in 1920 he was appointed professor of physics at Washington University, St. Louis, Missouri. The main part of his career however was spent at the University of Chicago where he served as professor of physics from 1923 to 1945. Compton then returned to the University of Washington first as chancellor and then (1953–61) as professor of natural philosophy.

Compton is best remembered for the discovery and explanation in 1923 of the effect named for him for which, in 1927, he shared the Nobel Prize for physics with Charles T. R. Wilson. He was investigating the scattering of x-rays by light elements such as carbon, and found that some of the scattered radiation had an increased wavelength, an increase that varied with the angle of scattering. According to classical physics there should be no such change, for it is difficult to see how the scattering of a wave can increase its wavelength, and Compton was led to seek its explanation elsewhere.

He thus assumed that the x-rays also exhibited particle-like behavior. Hence they could collide with an electron, being scattered and losing some of their energy in the process. This would lead to a lowering of the frequency with a corresponding increase in the wavelength. Compton went on to work out the formula that would predict the change of wavelength produced in the secondary x-rays and found that his precise predictions were fully confirmed by measurements made of cloud–chamber tracks by Wilson. Significantly, this was to provide the first hard experimental evidence for the dual nature of electromagnetic radiation; that is, that it could behave both as a wave and a particle. This would be developed much further in the 1920s as one of the cornerstones of the new quantum physics.

In the 1930s Compton concentrated on a major investigation into the nature of cosmic rays. The crucial issue, following the work of Robert Millikan, was whether or not a variation in the distribution of cosmic rays with latitude could be detected. Such an effect would show that the rays were charged particles, deflected by the Earth's magnetic field, and not electromagnetic radiation. As a result of much travel and the organization of a considerable amount of the research and measurements of others Compton was by 1938 able to establish conclusively that there was a clearly marked latitude effect.

During the war Compton was an important figure in the manufacture of the atomic bomb as a member of the committee directing research on the Manhattan project. He also set up at Chicago the Metallurgical Laboratory, which acted as a cover for the construction of the first atomic pile under the direction of Enrico Fermi and took responsibility for the production of plutonium. Compton later wrote a full account of this work in his book Atomic Quest (1956).

The American physicist Arthur Holly Compton (1892-1962) discovered the "Compton effect" and the proof of the latitude intensity variation. He also played a critical role in the development of the atomic bomb.

Arthur Compton was born in Wooster, Ohio, on Sept. 10, 1892, the youngest child of Elias and Otelia Compton. It was midway during Arthur's early formal education that he became interested in science and carried out his first amateur researches. Although he wrote an intelligent student essay on the mammoth, it was chiefly astronomy and aviation that stimulated him. He purchased a telescope and photographed constellations and (in 1910) Halley's comet. Later he constructed and flew a 27-foot-wingspan glider.

During his undergraduate years at the College of Wooster (1909-1913) Compton had to choose a profession. His father encouraged him to devote his life to science. On his graduation from Wooster, therefore, Arthur decided to pursue graduate study, obtaining his master's degree in physics from Princeton University in 1914; in 1916 he obtained his doctoral degree. Immediately after receiving his degree, Compton married Betty Charity McCloskey, a former Wooster classmate; the Comptons had two sons.

Compton Effect

Compton's first position was as an instructor in physics at the University of Minnesota (1916-1917), where he continued his x-ray researches. Leaving Minnesota, he became a research engineer at the newly established Westinghouse laboratory in East Pittsburgh, where he remained from 1917 to 1919, doing original work on the sodium-vapor lamp and developing instrumentation for aircraft. He left Westinghouse because he came to recognize that fundamentally his interest was not in industrial research but in pure research. In particular, he had become intrigued by a recent observation of the English physicist C. G. Barkla, who had scattered hard x-rays from aluminum and found that the total amount of scattered radiation was less than that predicted by a wellknown formula of J. J. Thomson. Compton found that he could account for Barkla's observation by assuming that the electrons in the scatterer were very large and therefore diffracting the incident radiation.

Anxious to pursue these studies further, Compton applied for and received a National Research Council fellowship to work with perhaps the foremost experimentalist of the day, Ernest Rutherford, at the Cavendish Laboratory in England. Compton's year in the extremely stimulating intellectual atmosphere at the Cavendish, during which time he carried out gamma-ray scattering experiments and pondered his results, marked a turning point in his career, as he became convinced that he was on the track of a very fundamental physical phenomenon.

Desiring to pursue it further on his own, Compton returned to the United States in 1920 to accept the Wayman Crow professorship of physics at Washington University in St. Louis. There he scattered x-rays from various substances and, eventually, analyzed the scattered radiation by use of a Bragg spectrometer. By the fall of 1922 he had definite experimental proof that x-rays undergo a distinct change in wavelength when scattered, the exact amount depending only on the angle through which they are scattered. Compton published this conclusion in October 1922 and within 2 months correctly accounted for it theoretically. He assumed that an x-ray - a particle of radiation - collides with an electron in the scatterer, conserving both energy and momentum. This process has since become famous as the Compton effect, a discovery for which he was awarded the Nobel Prize of 1927. The historical significance of Compton's discovery was that it forced physicists for the first time to seriously cope with Einstein's long-neglected and revolutionary 1905 light-quantum hypothesis: in the Compton effect an x-ray behaves exactly like any other colliding particle.

Cosmic-ray Work

While the discovery of the Compton effect was undoubtedly Compton's single most important contribution to physics, he made many others, both earlier and later. He proved in 1922 that x-rays can be totally internally reflected from glass and silver mirrors, experiments which eventually led to precise values for the index of refraction and electronic populations of substances, as well as to a new and more precise value for the charge of the electron. After Compton left Washington University for the University of Chicago in 1923 (where he later became Charles H. Swift distinguished service professor in 1929 and chairman of the department of physics and dean of the physical sciences in 1940), he reactivated a very early interest and developed a diffraction method for determining electronic distributions in atoms. Still later he and J. C. Stearns proved that ferro-magnetism cannot be due to the tilting of electronic orbital planes.

Perhaps the most important work Compton carried out after going to Chicago was his work on cosmic rays. Realizing the importance of these rays for cosmological theories, Compton developed a greatly improved detector and convinced the Carnegie Institution to fund a world survey between 1931 and 1934. The globe was divided into nine regions, and roughly 100 physicists divided into smaller groups sailed oceans, traversed continents, and scaled mountains, carrying identical detectors to measure cosmic-ray intensities.

The most significant conclusion drawn from Compton's world survey was that the intensity of cosmic rays at the surface of the earth steadily decreases as one goes from either pole to the Equator. This "latitude effect" had been noted earlier by the Dutch physicist J. Clay, but the evidence had not been conclusive. Compton's survey therefore proved that the earth's magnetic field deflects at least most of the incident cosmic rays, which is only possible if they are charged particles. Compton's world survey marked a turning point in knowledge of cosmic rays.

Atomic Bomb and Postwar Endeavors

When World War II broke out, Compton was called upon to assess the chances of producing an atomic bomb. If it were possible to develop an atomic bomb, Compton believed it should be the United States that had possession of it. Detailed calculations on nuclear fission processes proved that the possibility of developing this awesome weapon existed. Compton recommended production, and for 4 years thereafter, as director of the U.S. government's Plutonium Research Project, he devoted all of his administrative, scientific, and inspirational energies to make the bomb a reality.

Compton was under extraordinary pressure as he made arrangements for the purification of uranium and the production of plutonium and many other elements that went into the construction of the atomic bomb. Ultimately, Compton was asked for his personal opinion as to whether the bomb should be dropped on Hiroshima. He gave an affirmative response in the firm conviction that it was the only way to bring the war to a swift conclusion and thereby save many American and Japanese lives.

Between 1945 and 1953 Compton was chancellor of Washington University in St. Louis and strove unceasingly to make that institution a guiding light in higher education. Between 1954 and 1961, as distinguished service professor of natural philosophy, he taught, wrote, and delivered lectures to many groups and, as always, served on numerous boards and committees. In 1961 he became professor-at-large, intending to divide his time between Washington University, the University of California at Berkeley, and Wooster College. His plans were cut short by his sudden death on March 15, 1962, in Berkeley.

Compton was an extraordinarily gifted human being. At the age of 35 he won the Nobel Prize and was also elected to the National Academy of Sciences; later, he was elected to numerous other honorary societies, both foreign and domestic. He received a large number of honorary degrees, medals (including the U.S. government's Medal for Merit), and other honors. In spite of his many achievements and honors, however, he remained a modest and warm human being.

Further Reading

The Cosmos of Arthur Holly Compton, edited by Marjorie Johnston (1968), contains Compton's "Personal Reminiscences," a selection of his writings on scientific and nonscientific subjects, and a bibliography of his scientific writings. Compton discusses his role in the development of the atomic bomb in Atomic Quest (1956). The early life of the Compton family is the subject of James R. Blackwood, The House on College Avenue: The Comptons at Wooster, 1891-1913 (1968). General works on modern physics which discuss Compton include Gerald Holton and Duane H.D. Roller, Foundations of Modern Physical Science (1958); Henry A. Boorse and Lloyd Motz, eds., The World of the Atom (2 vols., 1966); and Ira M. Freeman, Physics: Principles and Insights (1968).

Arthur Holly Compton
Arthur Holly Compton on the cover of Time magazine, January 13, 1936.
Born	September 10, 1892(1892-09-10) Wooster, Ohio, USA
Died	March 15, 1962 (aged 69) Berkeley, California, USA
Nationality	United States
Fields	Physics
Institutions	University of Chicago Washington University in St. Louis
Alma mater	College of Wooster Princeton University
Doctoral advisor	Owen Willans Richardson H. L. Cooke
Doctoral students	Winston H. Bostick Robert S. Shankland
Known for	Compton effect Compton length Compton scattering Compton wavelength Compton shift
Notable awards	Nobel Prize for Physics (1927)
Religious stance	Presbyterian
Notes Compton is the son of Elias Compton, brother of Wilson Compton and Karl Taylor Compton, and father of John Joseph Compton.

Arthur Holly Compton (September 10, 1892 – March 15, 1962) was an American physicist and Nobel laureate in physics for his discovery of the Compton effect. He served as Chancellor of Washington University in St. Louis from 1945 to 1953.

Contents 1 Biography 1.1 Early years 1.2 Wartime activities 1.3 Washington University in St. Louis 1.4 Personal details 2 Legacy 2.1 Free Will 3 Bibliography 4 References 5 External links

Biography

Early years

Arthur Compton was born in Wooster, Ohio in 1892 to Elias and Otelia Compton. They were an academic family. His father Greg was dean of Wooster University (later The College of Wooster), which Arthur attended, and also became a member of the Alpha Tau Omega Fraternity. His eldest brother Zack also attended Wooster University, became a physicist, and was later president of MIT. His second brother Wilson Martindale Compton also attended Wooster University and became a diplomat and president of the State College of Washington, later Washington State University. All three brothers earned their Ph.D. degrees from Princeton University.^[1]

Around 1913, Arthur Compton devised a demonstration method for the Earth's rotation. In 1918, he began studying X-ray scattering. In 1922, Compton found that X-ray wavelengths increase due to scattering of the radiant energy by "free electrons". The scattered quanta have less energy than the quanta of the original ray. This discovery, known as the "Compton effect," or "Compton scattering" demonstrates the "particle" concept of electromagnetic radiation and earned Compton the Nobel Prize in physics in 1927. Compton developed the method for observing at the same instant individual scattered X-ray photons and the recoil electrons (developed with Alfred W. Simon). In Germany, Walther Bothe and Hans Geiger independently developed a similar method.

Wartime activities

In 1941, along with Vannevar Bush, head of the wartime Office of Scientific Research and Development (OSRD), and Ernest Lawrence, the inventor of the cyclotron, Compton helped to take over the then-stagnant American program to develop an atomic bomb. Compton was placed in charge of the OSRD's S-1 Committee charged with investigating the properties and manufacture of uranium. In 1942, Compton appointed Robert Oppenheimer as the Committee's top theorist. When the Committee's work was taken over by the Army in the summer of 1942, it became the Manhattan Project.

Immediately after the Japanese attack on Pearl Harbor on December 7, 1941, Compton gained support for consolidating plutonium research at the University of Chicago and for an ambitious schedule that called for producing the first atomic bomb in January 1945, a goal that was missed by only six months. "Metallurgical Laboratory" or "Met Lab" was the "cover" name given to Compton's facility. Its objectives were to produce chain-reacting "piles" of uranium to convert to plutonium, find ways to separate the plutonium from the uranium and to design a bomb. In December 1942, underneath Chicago's Stagg Field, a team of Met Lab scientists directed by Enrico Fermi achieved a sustained chain reaction in the world's first nuclear reactor. Throughout the war, Compton would remain a prominent scientific adviser and administrator. In 1945, he served, along with Lawrence, Oppenheimer, and Fermi, as part of the Scientific Panel which advised for the military use of the atomic bomb against Japanese cities.^[2]

Washington University in St. Louis

Compton returned to Washington University in St. Louis, where he had served as Head of the Department of Physics from 1920 to 1923, when he was inaugurated as the university's ninth Chancellor in 1946.

During Compton's time as Chancellor, the university formally desegregated its undergraduate divisions in 1952, named its first female full professor, and enrolled a record number of students as wartime veterans returned to the United States. His reputation and connections in national scientific circles allowed him to recruit many nationally renowned scientific researchers to the university. Despite Compton's accomplishments, he was criticized then, and subsequently by historians, for moving slowly toward full racial integration, making Washington University the last major institution of higher learning in St. Louis to open its doors to African Americans.^[3]

Compton resigned as Chancellor in 1953, but remained on the faculty until his retirement from the full-time faculty in 1961.

Personal details

Along with being an academic his father was a Presbyterian clergyman. At least for a time Arthur Compton was a deacon at a Baptist church. He also played the mandolin and was a scientific glassblower.^[4]

Legacy

Compton is buried in the Wooster Cemetery in Wooster, Ohio. The crater Compton on the Moon is co-named for Arthur Compton and his brother Karl. The physics research building at Washington University in St Louis is named in his honor. The University of Chicago Residence Halls remembered Compton and his achievements by dedicating Compton House in his honor. Compton also has a star on the St. Louis Walk of Fame.

The Arthur H. Compton House in Chicago is listed as a National Historic Landmark.

Compton also invented a more gentle, elongated, and ramped version of the speed bump called a "Holly hump," many of which are on the roads of the Washington University in St. Louis campus.

NASA's Compton Gamma Ray Observatory was named in honor of Compton. The Compton effect is central to the gamma ray detection instruments aboard the observatory.

Free Will

Compton was one of a handful of scientists and philosophers to propose a two-stage model of free will. Others include William James, Henri Poincaré, Karl Popper, Henry Margenau, and Daniel Dennett.

In 1931, Compton championed the idea of human freedom based on quantum indeterminacy and invented the notion of amplification of microscopic quantum events to bring chance into the macroscopic world. In his somewhat bizarre mechanism, he imagined sticks of dynamite attached to his amplifier, anticipating the Schrödinger's Cat paradox.^[5]

Reacting to criticisms that his ideas made chance the direct cause of our actions, Compton clarified the two-stage nature of his idea in an Atlantic Monthly article in 1955. First there is a range of random possible events, then one adds a determining factor in the act of choice.

"A set of known physical conditions is not adequate to specify precisely what a forthcoming event will be. These conditions, insofar as they can be known, define instead a range of possible events from among which some particular event will occur. When one exercises freedom, by his act of choice he is himself adding a factor not supplied by the physical conditions and is thus himself determining what will occur. That he does so is known only to the person himself. From the outside one can see in his act only the working of physical law. It is the inner knowledge that he is in fact doing what he intends to do that tells the actor himself that he is free." ^[6]

Bibliography

• Compton, Arthur (1918). "American Physical Society address (Dec 1917)", Physical Review, Series II.
• Compton, Arthur (1923). "A Quantum Theory of the Scattering of X-Rays by Light Elements", Physical Review, 21(5), 483 – 502.
• Compton, Arthur (1935). The Freedom of Man, New Haven: Yale University Press.
• Compton, Arthur (1940). The Human Meaning of Science, Chapel Hill: University of North Carolina Press.
• Compton, Arthur (1956). Atomic Quest, New York: Oxford University Press.
• Compton, Arthur (1967). The Cosmos of Arthur Holly Compton, New York: Alfred A. Knopf; edited by Marjorie Johnston
• Compton, Arthur (1973). Scientific Papers of Arthur Holly Compton, Chicago: University of Chicago Press; edited by Robert S. Shankland.

References

1. ^ The Compton Brothers
2. ^ Recommendations on the Immediate Use of Nuclear Weapons
3. ^ Amy M. Pfeiffenberger, "Democracy at Home: The Struggle to Desegregate Washington University in the Postwar Era," Gateway-Heritage (Missouri Historical Society), vol. 10, no. 3 (Winter 1989), pp. 17-24.
4. ^ Time Magazine: January 13, 1936
5. ^ SCIENCE, 74, p.1911, August 14, 1931.
6. ^ "Science and Man’s Freedom", in The Cosmos of Arthur Holly Compton, 1967, Knopf, p.115

External links

• Arthur Compton biographical entry at Washington University in Saint Louis
• Arthur Compton Annotated bibliography from the Alsos Digital Library for Nuclear Issues
• Arthur Holly Compton on Information Philosopher
• Nobelprize.com Biography
• Arthur Compton at Find a Grave

v • d • e Chancellors of Washington University in St. Louis Joseph Gibson Hoyt (1858) · William Chauvenet (1863) · Abram Litton (1869) · William Greenleaf Eliot (1870) · Marshall Snow (1887) · Winfield Scott Chaplin (1891) · Marshall Snow (1907) · David F. Houston (1908) · Frederic Aldin Hall (1917) · Herbert S. Hadley (1923) · George R. Throop (1927) · Henry Brookings Wallace (1944) · Arthur Compton (1946) · Ethan A.H. Shepley (1954) · Carl Tolman (1961) · Thomas H. Eliot (1962) · William Henry Danforth (1971) · Mark S. Wrighton (1995)

v • d • e Nobel Laureates in Physics Jean Perrin (1926) · Arthur Compton / Charles Wilson (1927) · Owen Richardson (1928) · Louis de Broglie (1929) · C. V. Raman (1930) · Werner Heisenberg (1932) · Erwin Schrödinger / Paul Dirac (1933) · James Chadwick (1935) · Victor Hess / Carl Anderson (1936) · Clinton Davisson / George Thomson (1937) · Enrico Fermi (1938) · Ernest Lawrence (1939) · Otto Stern (1943) · Isidor Rabi (1944) · Wolfgang Pauli (1945) · Percy Bridgman (1946) · Edward Appleton (1947) · Patrick Blackett (1948) · Hideki Yukawa (1949) · Cecil Powell (1950) Complete roster | (1901–1925) | (1926–1950) | (1951–1975) | (1976–2000) | (2001–present)

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Persondata
NAME	Compton, Arthur
ALTERNATIVE NAMES	Compton, Arthur Holly
SHORT DESCRIPTION	American Physicist
DATE OF BIRTH	September 10, 1892
PLACE OF BIRTH	Wooster, Ohio, U.S.
DATE OF DEATH	March 15, 1962
PLACE OF DEATH	Berkeley, California, U.S.

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