Born in Morrison, Illinois, Robert Andrew Millikan was the second son of the Reverend Silas Franklin Millikan and Mary Jane Andrews. When Millikan was seven, his family moved to Maquoketa, Iowa, where he attended high school. In 1886 he entered Oberlin College in Ohio. In 1887 he enrolled in several classics classes there, and because he did quite well in Greek, at the end of his sophomore year, he was asked to teach an introductory-level physics class. He enjoyed teaching physics and accepted a two-year teaching post at Oberlin upon graduation in 1891. It was during this period that he developed an even keener interest in physics.
In 1893 Millikan began his doctoral work at Columbia University, receiving a Ph.D. in 1895. After travelling to Germany, he eventually accepted a faculty position at the University of Chicago. It was as a teacher and textbook author that Millikan first made his mark. He wrote or co-wrote a number of elementary physics texts that became the classics in this field. However, while valued activities, they did not lead to his promotion to full professor. Determined to ascend in academic rank, Millikan began his research into the charge on the electron.
At the time, the debate over whether or not atoms were real had almost played out, but the questions surrounding the true nature of the electron were still unanswered. Although the work of the English physicist J. J. Thomson had elucidated the charge-to-mass ratio, determining that the electron had a discrete, fixed charge and mass remained.
Being an experimentalist, Millikan used a tiny, submillimeter drop of oil suspended between capacitor plates to measure the incremental charge on an electron. His reasoned that the oil drop would pick up a charge due to friction as it entered the region between the plates. By ionizing the atmosphere and monitoring the motion of multiple drops, he was able to compare the time that the drop took to fall under the influence of gravity and with the electrical plates off, against the time that it took for the drop to climb under the influence of applied voltage . The interaction of the drop with the electric field always occurred in discrete units, indicating that the electron charge was a single value, and that it was the same value for all different forms of electricity.
Millikan's oil-drop experiment settled the argument and determined accurately (within one part in a thousand) both the charge and, by virtue of the charge-to-mass ratio, the mass of the electron. Both numbers allowed the Danish physicist Niels Bohr to finally calculate Rydberg's constant and provided the first and most important proof of the new atomic theory .
Millikan went on to demonstrate the photoelectron effect, providing a valuable proof of Albert Einstein's equations. His experiments also aided both Einstein and Bohr in their later research efforts. In 1923 he was awarded a Nobel Prize in physics for both his work in determining the charge on the electron and exploring the photoelectric effect.
Robert Millikan is the scientist who measured the charge on an electron using his famous oil drop experiment.
The scientist who first measured the charge of an electron was Robert A. Millikan in 1909 through his famous oil drop experiment.
Robert A. Millikan conducted these experiments. His discoveries are instrumental to atomic and particle theory.
Robert A. Millikan conducted his famous oil drop experiment at the University of Chicago in the early 20th century. This experiment allowed him to accurately measure the charge of an electron for the first time.
Robert Millikan conducted his famous oil drop experiment in 1909, which helped to determine the charge of an electron. This experiment led to his noteworthy discovery in 1913 of the fundamental unit of electric charge.
He discovered the charge of the electron.
Robert Millikan measured the electrical charge of the electron.
the charge of the electron
1909
Robert Millikan was the first Physicist to measure the electrical charge of the electron.
1909
Robert Millikan was the first to measure the electrical charge of an electron.
Robert Millikan
Robert Andrews Millikan has written: 'The electron' 'Science and the new civilization'
Any, Robert Millikan determined the electrical charge of electron.
Robert Millikan discovered the change of electron using the oil drop experiment in 1909. He was able to measure the charge of an electron accurately using this method.
he found the measurement or electron charge