Robert Millikan spent ten years trying to prove Einstein wrong and confirmed him
When Einstein proposed in 1905 that light comes in particles, Robert Millikan was sure the idea must fail, because a mountain of experiments said light was a wave. He devoted about a decade to testing it, and his 1914 results matched Einstein's predictions in every detail.
Even then Millikan resisted. In 1916 he wrote that Einstein's photoelectric equation described the effect very accurately yet had no satisfactory theoretical footing. Only in his 1950 autobiography did he concede that his data allowed hardly any reading except the photon theory. The same experiments also yielded a measurement of the Planck constant, drawn from photoelectric emission graphs for different metals.
His other famous test measured the charge of a single electron. From 1909, with graduate student Harvey Fletcher, he balanced tiny charged oil droplets against gravity between two metal plates and calculated the charge from the electric field. Over many droplets the charges came out as whole-number multiples of one value, about 1.592 × 10^-19 coulomb, slightly below today's figure. The apparatus made the case that charge comes in discrete lumps; Charles Steinmetz of General Electric changed his mind after using it. Millikan took sole credit, while Fletcher kept that bargain secret until he died, and the 1923 Nobel Prize in Physics followed.
Born in Morrison, Illinois, on 22 March 1868, Millikan stumbled into physics at Oberlin College. After his sophomore year his Greek professor asked him to teach elementary physics, brushing off his protest that he knew none; he spent the summer of 1889 cramming from a textbook. He later co-wrote introductory textbooks that set conceptual problems instead of plug-in exercises, though as late as 1927 his text still affirmed the ether.
From 1921 until 1945 he ran physics at Caltech and chaired its governing council, helping turn a small Pasadena college into a leading research institution. There he coined the term cosmic rays and argued they were photons, the birth cries of new atoms; Arthur Compton showed they were charged particles, since Earth's magnetic field bends them. After the 1933 Long Beach earthquake he chaired a committee urging tougher building codes. He died in San Marino, California, on 19 December 1953.
Source: Robert Millikan
