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Physics and War : 1940-1945

MIT AND THE SECOND WORLD WAR

By the end of the 1930s, MIT's Physics Department was fortified with new recruits and more students, and the president of MIT was once again a physicist. As the Second World War loomed, the MIT community pledged its support to the Allied effort. For the physicists, this would manifest itself in two distinct ways: working on wartime projects away from and hosted at MIT, and aiding in the technical education of military officers so that they could fight effectively on the increasingly technical battlefield. World War II, which early on was labeled "the physicist's war," would change the nature of physics everywhere, and especially at MIT.

THE RAD LAB AT MIT

The dome of the Rad Lab's rooftop radar laboratory overlooks the Charles River.
The dome of the Rad Lab's rooftop radar laboratory overlooks the Charles River.

In 1940, a delegation of British scientists brought a new invention to the shores of the United States. The small and innocuous-looking radio tube known as a cavity magnetron had grown out of work the United Kingdom had been pursuing for years: to use reflected radio waves to detect planes and boats at a distance. It had become clear to the British that they would not be able to develop the technology alone in time to fight off the overwhelming airpower of the German Luftwaffe.

Karl Compton, President of MIT, had been involved in the American investigation into microwave research for defense purposes from very early on. Microwave research at MIT had been conducted since the 1930s, though it was not until the disclosure of the cavity magnetron to the Americans that the possibility of developing truly useful radar for use during war became realistic.

BUILDING 20

Trucks line up to deliver materials and remove radar sets at MIT's Building 20, home base for the Rad Lab.
Trucks line up to deliver materials and remove radar sets at MIT's Building 20, home base for the Rad Lab.

MIT was chosen as the site to host a new laboratory devoted specifically to radar research. Over the course of the war, the Radiation Laboratory at MIT (named as such to obscure its purpose from prying eyes) advanced and accelerated radar development, turning out new iterations of radar units with great speed, testing them first on the edge of the Charles River and later over the skies and seas of Europe and Asia.

The head of the Physics Department, John C. Slater, made a great contribution to radar research when he was called upon to aid in the development of magnetron theory. His work contributed in the development of the x-band magnetron, an improvement on the cavity magnetron. Eventually the Rad Lab grew to have an annual budget of $13 million, a staff of over 4,000, and industrial contracts worth $1.5 billion; it was, as such, the single-largest war research laboratory.

THE MOBILIZED DEPARTMENT

X-rays of captured Japanese munitions taken in Van de Graaff and Buechner's high-voltage laboratory during the war.
X-rays of captured Japanese munitions taken in Van de Graaff and Buechner's high-voltage laboratory during the war.

Practically every member of the MIT Physics Department was involved in some form of war work. Robert Van de Graaff and William W. Buechner developed high-voltage x-ray machines that could be used to examine American castings and munitions for defects, and proved valuable for examining captured enemy munitions as well. The Radioactivity Laboratory, under Robley D. Evans, operated its cyclotron nearly twenty-four hours a day in order to generate radioisotopes for medical purposes. The Spectroscopy Laboratory run by George Harrison continued the analysis of chemicals it had begun in the 1930s, only for a new patron: the Manhattan Project, the top-secret crash program to build an atomic bomb.

Department members worked on camouflage (specifically light-scattering paint that made daylight bombing raids safer), guided bombs and missiles, and noise reduction inside tanks. Philip M. Morse, whose experience in acoustics made him an expert on the latter issue, started his war work by developing hydrophones that could detect submarines for the Navy, and were quickly put into use in the field. He would later use this expertise to develop new strategies, based in a rigorous understanding of statistics, for tackling anti-submarine warfare. Morse's pioneering work in applying scientific methods to wartime strategic problems was the American equivalent of what was being called Operations Research in Britain, and became one of science's most far reaching contributions not only to World War II, but to warfare in general.

A CHANGED WORLD

An MIT-produced radar scope shows Allied invasion of France across the English Channel on D-Day, 1944.
An MIT-produced radar scope shows Allied invasion of France across the English Channel on D-Day, 1944.

It has often been said that while the atomic bomb ended the war, it was radar that won the war. Radar had grown to a crucial technology used daily in every theater of battle. Given this truism, as well as other wartime work done at MIT and by MIT affiliates, it is not an exaggeration to say that the Institute had a massive impact on the technical aspects of the Second World War. Physics in particular was given the lion's share of the credit for the success of the Allied forces, and World War II is often dubbed "the physicist's war."

The war also changed MIT, and changed physics in particular. Some of the changes are obvious from the figures alone: in 1946, the total Institute annual budget was three times larger than the largest pre-war budget, of which half was devoted strictly to research. Some changes were more subtle. Whether in the massive factories and secretive laboratories of the Manhattan Project, or in the Rad Lab itself, MIT physicists were exposed to a new form of work where the line between pure research and applicable technology was impossibly blurred, where the resources at hand were incomparably larger than before, and where the government played an unprecedented role in the funding of research.

Bibliography

For a readable account of the Rad Lab, see Daniel J. Kevles, The physicists: the history of a scientific community in modern America (New York: Knopf, 1977).

For a detailed, definitive history of radar through the Second World War, including the Rad Lab, see Henry E. Guerlac, Radar in World War II (New York: American Institute of Physics, 1987).

For accounts of non-radar related work at MIT and by MIT physicists, see John E. Burchard, Q.E.D.: MIT in World War II (New York: Technology Press, 1948); and John C. Slater, "History of the MIT Physics Department, 1930-1948," unpublished m.s. [1948], Box 171, Folder 1, Records of the Massachusetts Institute of Technology, Office of the President, 1930-1959 (A4), Institute Archives, MIT.