oildropeksperimentet

Oildropeksperimentet, also known as the "Oil Drop Experiment," was a pivotal scientific procedure conducted by Robert A. Millikan in the early 20th century. Its primary aim was to measure the fundamental electric charge of the electron with high precision. The experiment was carried out between 1909 and 1911 and provided crucial evidence supporting the quantization of electric charge.

The setup involved generating small oil droplets, which were sprayed into a region between two metal plates. By employing an atomizer, Millikan introduced these droplets into a vacuum chamber, where they became electrically charged through various means such as ionization. The droplets' motions were observed through a microscope, and their velocities were measured both with the electric field turned off and on. When an electric field was applied between the plates, it exerted a force on the charged droplets, counteracting gravity and allowing their charges to be deduced.

By carefully adjusting the electric field to suspend the droplets or make them move at controlled velocities, Millikan could determine the magnitude of the charge on individual droplets. Repeated measurements of many droplets revealed that their charges were integer multiples of a basic unit, which he identified as the elementary charge e, approximately 1.602×10^-19 coulombs.

The oildropeksperiment is considered a landmark in atomic physics, as it provided the first accurate measurement of the electron's charge and lent strong support to the emerging quantum theory. It also demonstrated the particle-like nature of the electron and laid the groundwork for future research in electromagnetism and quantum mechanics. Robert Millikan was awarded the Nobel Prize in Physics in 1923 partly for this groundbreaking work.