By: Kaylen McMahan
Robert Andrews Millikan was born in Illinois. He loved science.
Millikan went to Oberlin College in 1891 and received his doctorate from Colombia University in He went on to teach at the University of Chicago, where he became a fulltime professor in 1910.
In 1909 Millikan began experimenting with electric charge. He wanted to find out the electric charge of a single electron. He obtained these results in 1910 with his famous oil-drop experiment, where he exchanged water for oil. Oil-drop experiment
Oil Drop Experiment in Depth Over a ten-year program of experimentation, Robert Millikan devised the apparatus to verify Einstein's theory. Inside an evacuated glass bulb, a plate of an alkali metal, such as lithium, sodium, or potassium, was mounted on a wheel which moved past a scraper knife and then into the path of monochromatic light at various frequencies. Millikan measured the voltage required to prevent the induced current. The graph of incident light frequency vs. voltage was a straight line. Einstein's equation was verified. The main failure was that there was no way of isolating an individual particle. For his experiment Millikan used very tiny oil droplets (due to its low evaporation rate). The oil droplets picked up a charge due to friction with oxygen molecules. They were also subjected to radiation source so that the probability of charged oil drops will be high in the chamber. These droplets were allowed to fall initially under the influence of gravity and air resistance. By focusing on a single oil drop its terminal velocity was calculated. Then the oil drops were subjected to electric field. Photoelectric Effect
He studied Einstein’s equation in He then used this reserearch that he gained from experimentation to gain an exact value of Planck’s constant.
In 1921 he went on to become the director of the Norman Bridge Laboratory of Physics at CalTech. It was here that he studied radiation that physicist Victor Hess had detected came from outer space (the sun). Millikan proved that radiation had indeed come from outer space. He named this radiation ‘cosmic rays’. Until Millikan retired from working as chairman of the executive council at CalTech, he transformed CalTech into one of the primary researching schools in the nation.
He was awarded the Nobel Prize in 1923 for determining the charge of an electron in 1913 and Planck’s constant in His research with the oil drop experiment and photoelectric effect won him this award. He studied with Max Planck in Germany and he also studied withHermann Nernst at Göttingen. Man of ‘Nobel’ Stature
Millikan, Robert Andrews. ( 2010). In Encyclopædia Britannica. Retrieved February 24, 2010, from Encyclopædia Britannica Online School Edition: http://school.eb.com/eb/article Millikan, Robert Andrews. [Photograph]. Retrieved February 24, 2010, from Encyclopædia Britannica Online School Edition: http://school.eb.com/eb/art RM, p. (2003). Robert Andrews Millikan ( ). Hutchinson's Biography Database, 1. Retrieved from History Reference Center database. Salem Press/Magill, B. (1999). Millikan Explains Cosmic Rays. Great Scientific Achievements (p. 241). US: Salem Press/Magill Books. Retrieved from History Reference Center database Salem Press/Magill, B. (1999). Millikan Conducts His Oil-Drop Experiment. Great Scientific Achievements (p. 145). US: Salem Press/Magill Books. Retrieved from History Reference Center database. Audio: Dream on as performed by Aerosmith