Physicists disagreed among themselves over whether cathode rays were particles--a logical assumption, since they carried a charge--or whether they took the form of waves.
Confirms Nature of Cathode Rays
In 1895 Perrin settled the debate simply and decisively using a cathode-ray discharge tube attached to a larger, empty vessel. When the discharge tube generated cathode rays, the rays passed through a narrow opening into the vessel, and produced fluorescence on the opposite wall. Nearby, an electrometer, which measures voltage, detected a small negative charge. But when Perrin deflected the cathode rays with a magnetic field so they fell on the nearby electrometer, the electrometer recorded a much larger negative charge. This demonstration was enough to prove conclusively that cathode rays carried negative charges and were particles, rather than waves. This work laid the basis of later work by physicist J. J. Thomson, who used Perrin's apparatus to characterize the negatively charged particles, called electrons, which were later theorized to be parts of atoms.
In 1897 Perrin married Henriette Duportal, with whom he had a son and a daughter. He received his doctorate the same year, and began teaching a new course in physical chemistry at the University of Paris (the Sorbonne).
This is a free page. This page contains 191 words. This
biography contains 2,388 words (approx. 8 pages at 300
words per page).
Read the rest of this Biography with our Jean Baptiste Perrin Access Pass.
