The Millikan trial was an experiment conducted by Robert Millikan and Harvey Fletcher in 1909.
The purpose of the experiment by Robert Millikan and Harvey Fletcher in 1909 was to determine the charge of a single electron. They did this by holding a small oil drop floating between two capacitor plates. If you know the electric field strength and the mass of the oil drop then you can accurately determine the charge of the droplet. By doing this for a large number of these little droplets, they found that the measured values were always a multiple of the same load. They interpreted this as a single electron charge: 1.602 × 10 coulomb.
Background Robert A. Millikan in 1891Since 1909, when he was a professor at the University of Chicago, Millikan, with much input from Fletcher, worked on the oil drop experiment. Since that time, generations of natural science students have repeated the experiment - with varying degrees of success. After publication in 1910, the found value for the electron cargo was questioned by Felix Ehrenhaft. A controversy between the two physicists was the result. After improving his arrangement, he published his results in 1913. The so-called elementary charge is one of the fundamental physical constants, and its precise determination is of great importance. This experiment measures the force on extremely small charged droplets of oil that are floated against gravity in between two charged metal sheets. If the electric field strength, the size of the droplet and the specific mass of the oil are known, the charge on the droplet can be determined. By repeating the experiment for large numbers of droplets, Millikan indicated that the load found was always a multiple of an 'elemental' value (1.602 × 10 coulomb). This can be explained as being the charge of a single electron.
Although there was a suspicion that subatomic particles would exist around 1891, not everyone was convinced. By trials with cathode rays in 1897, Joseph John Thomson discovered negatively charged 'bodies', as he called them, 1000 times as much as hydrogen atoms. Similar results were found by George FitzGerald and Walter Kaufmann. Virtually everything that was known about electricity and magnetism could be explained on the basis that cargo is an unbroken quantity. The charm of this experiment is that it allows simple determination of a fundamental constant and provides a demonstration of the quantization of load. Thomas Edison had previously thought that the load was an infinitely divisible greatness, but was convinced of the contrary to have worked with Millikan and Fletcher's devices.
In recent years there has been a fuss about the 'selective' use of results by Millikan. The historian Gerald Holton noted that measurements were treated quite selectively. Holton (1978) pointed out that Millikan ignored a large set of measurements without clear reason. Experts have underlined this later, but some cosmetic surgery has been carried out on the results. The purpose of this was to assert that a measurement of e with an accuracy of ± 0.5% had occurred, while the actual accuracy was within ± 2%, which was still more accurate than any other, but Millikan determined that this would have led to "unnecessary discussion" in physical circuits.
In 1923 Millikan won the Nobel Prize for Physics - partly because of this experiment. The experiment has now been repeated by generations of physical education students, in which case they perceive how difficult it is to get a little closer to the true value of e and within Millikan's margin of error. Procedures experiments Simple setup for the test of
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