40 Fun Facts About Robert Millikan

Robert Millikan was studying which subject when his professor asked him to teach elementary physics?

Greek was Millikan's strong suit, and his professor insisted that anyone who did well in it could teach physics. Millikan spent a summer cramming from a textbook to stay ahead of the class.

Millikan spent a decade trying to disprove which physicist's 1905 particle theory of light?

Albert Einstein proposed that light arrives in packets, an idea Millikan was convinced had to be wrong. His own precise results matched the prediction in every detail, yet he doubted the interpretation for years.

Which name did Millikan coin for the mysterious radiation that grows stronger at high altitude?

Cosmic rays got their name from Millikan in the 1920s, after he confirmed the radiation was arriving from beyond Earth. Victor Hess had discovered it years earlier during daring balloon flights.

Which Caltech physicist cited Millikan's result as a warning about scientists fooling themselves?

Richard Feynman told Caltech's 1974 graduates that later experimenters nudged their results toward Millikan's slightly low electron charge. The accepted value crept upward only over many years.

Caltech took Millikan's name off its library in 2021 over his ties to which discredited movement?

Eugenics drew Millikan in as a trustee of the Human Betterment Foundation, which promoted compulsory sterilization. The Robert A. Millikan Library is now called Caltech Hall.

Millikan's droplet experiment first used which liquid, abandoned because it evaporated too fast?

Water came first, but each droplet shrank as it evaporated while Millikan was timing it. Switching to oil, which barely evaporates, kept every drop's mass steady.

In World War I, Millikan's National Research Council work targeted which German weapon?

Submarines were the target: as the council's vice chairman, Millikan played a major part in developing anti-submarine and meteorological devices.

Millikan's 1938 message to the far future was buried in a Westinghouse time capsule at which event?

New York World's Fair crowds arrived in 1939, and the capsule still lies fifty feet under Flushing Meadows, meant to stay sealed until the seventh millennium.

A large impact crater named for Robert Millikan lies in the northern hemisphere of which body?

Moon maps place Millikan crater on the far side, just north of a crater named for H. G. Wells, so it can never be seen from Earth.

In 1982 the United States honored Robert Millikan in its Great Americans series of which items?

Postage stamps in the Great Americans series showed Millikan on a 37-cent issue released on January 26, 1982. The series ran from 1980 to 2000.

Which graduate student ran the oil drop experiment with Millikan yet was left off the paper as an author?

Harvey Fletcher let Millikan publish alone in exchange for sole authorship of a related result he could use as his dissertation. The deal stayed secret until after his death in 1981.

Millikan's oil drop assistant later became known as the father of which audio technology?

Stereophonic sound was recorded by his Bell Labs team with conductor Leopold Stokowski in the early 1930s, among the earliest such recordings. He also built an early electronic hearing aid.

Millikan's electron charge came out slightly low because he misjudged which property of air?

Viscosity sets the drag on a falling droplet, so the error carried straight into the result. Millikan's figure still landed within about 0.6 percent of the modern value.

Which law of drag on a small sphere did Millikan use to size each falling oil droplet?

Stokes' law ties a tiny sphere's steady falling speed to its radius, so timing a drop with the field switched off revealed its weight. The law dates from 1851.

Which Austrian physicist feuded with Millikan after claiming charges smaller than the electron's?

Felix Ehrenhaft's claims were ultimately dismissed, but the unresolved dispute is widely believed to have cost Millikan the 1920 Nobel Prize. He won it three years later.

Whose measurement of the electron's charge-to-mass ratio let Millikan's result reveal its mass?

J. J. Thomson had found only the ratio, so neither quantity was known on its own. Once Millikan pinned down the charge, the mass followed by simple division.

Millikan's light experiments on clean metal surfaces gave a precise measurement of whose constant?

Planck's constant came out of his graphs of electron emission from various metals, measured between 1912 and 1915. Building the vacuum apparatus took years of work.

Which Nobel laureate argued against Millikan that radiation from space was charged particles?

Arthur Compton's worldwide survey found the rays stronger near the poles, steered by Earth's magnetic field as only charged particles could be. Millikan had insisted they were photons.

Which antimatter particle did Millikan's student Carl Anderson find in cloud chamber photographs?

Positron tracks confirmed Paul Dirac's prediction of a twin of the electron with the opposite charge. Anderson found them at Caltech while studying radiation from space under Millikan's supervision.

Which famous measurer of the speed of light invited Millikan to join his physics department in 1896?

Albert Michelson promised Millikan up to half his time for research, so he accepted even though another post paid twice the salary. Michelson later became the first American to win a science Nobel.

At which university's Ryerson Physical Laboratory did Millikan carry out the oil drop experiment?

Chicago hired Millikan as an assistant in 1896, and he stayed for a quarter of a century. A full professorship came only in 1910, after the oil drop work made his name.

Robert Millikan, who also enjoyed golf, was known as an enthusiastic player of which other sport?

Tennis was Millikan's game: his Nobel biography calls him an enthusiastic player, with golf as another recreation.

Millikan served on the organizing committee for which major event held in Los Angeles in 1932?

The Olympic Games came to Los Angeles in 1932 with Millikan on the organizing committee, a sign of how prominent the Caltech leader had become in the city's civic life.

After a 1933 Long Beach disaster, Millikan led a committee on safer building against which hazard?

Earthquakes became a public-safety cause after the Long Beach shock killed about 120 people. Millikan's committee of scientists, architects and builders urged stronger building codes in a report that June.

Millikan argued in lectures and several books that science could be reconciled with which pursuit?

Religion and science were allies for Millikan, a minister's son. When he told a 1930 scientific meeting that the Creator was still on the job, the remark made front-page news.

Millikan's oil drop experiment balanced gravity against which upward force between two metal plates?

Electric force from a voltage across the plates could be tuned until a charged drop hung motionless. From that balance and the drop's weight, Millikan worked out the charge it carried.

Millikan's Nobel Prize cited his work on the elementary charge and on which other effect?

Photoelectric measurements, in which light knocks electrons out of a metal, shared the 1923 citation with his work on the electron's charge.

For his doctorate, Millikan studied light from molten gold and silver at which federal facility?

The U.S. Mint gave Millikan the molten metal he needed to study how light from incandescent surfaces is polarized. The thesis earned him his doctorate in 1895.

Millikan's son Glenn married the daughter of which British mountaineer who died on Mount Everest?

George Mallory's daughter Clare married Glenn in 1938, and the family's bad luck with mountains continued: Glenn was killed by a falling rock while climbing in Tennessee in 1947.

Which East Coast university awarded Robert Millikan his doctorate in physics in 1895?

Columbia made Millikan a Fellow in Physics in 1893, and his professors there then urged him to spend a year at the universities of Berlin and Göttingen.

Millikan described radiation from space as which sounds made by atoms in interstellar space?

Birth cries was his phrase because he believed new atoms were continually being created in space, staving off the heat death of the universe. Rival scientists preferred to call them death wails.

Los Angeles renamed Millikan Middle School in 2022 to honor which jazz musician instead?

Louis Armstrong replaced Millikan on the Sherman Oaks school after a unanimous school board vote. Pomona College and a physics teaching award dropped the Millikan name as well.

Millikan sat with Marie Curie on the Committee on Intellectual Cooperation of which body?

The League of Nations committee brought leading researchers together after World War I, and Millikan served as its American member through the 1920s.

Millikan's youngest son Max, once a CIA assistant director, was an MIT professor of which subject?

Economics was Max Millikan's field, though his first degree, from Yale, was in physics. He went on to direct MIT's Center for International Studies.

Which medical device did Millikan's son Glenn invent in the early 1940s to protect military pilots?

Oximeter was Glenn Millikan's own word for the device, which clasped to a pilot's earlobe to track blood oxygen at altitude. It is regarded as the beginning of oximetry in medicine.

Caltech carried which name in 1917, when Millikan first began spending part of each year there?

Throop College of Technology honored Amos Throop, who founded it as a preparatory and vocational school in 1891. It took the name California Institute of Technology in 1920.

Which solar astronomer persuaded Millikan to leave the Midwest in 1921 and build up Caltech?

George Hale worked with Millikan on wartime research and afterwards bombarded him with requests to come west. Lavish funds and a free hand finally won the physicist over.

Robert Millikan earned his bachelor's degree in 1891 from which Ohio liberal arts college?

Oberlin kept Millikan on for two years after graduation to teach elementary physics, the job that first drew him toward science. He took a master's degree there in 1893.

Which job did Millikan hold for a short time after high school, before entering college in 1886?

Court reporter was only a brief stop for Millikan, who had grown up in rural Iowa as the son of a preacher and left for college at eighteen.

Millikan's hot-spark spectroscopy in the early 1920s extended which region of the spectrum?

Ultraviolet measurements by Millikan and Ira Bowen reached down toward X-rays, opening a stretch of the spectrum that earlier instruments could not explore.