Quantum Physics Laboratory University of Valencia.

Published on October 29, 2018

This video studies the experiment carried out in 1914 by the German scientists, James Franck and Gustav Hertz, which showed the quantization of the electron energies in atoms, that is, the existence of discrete atomic energy levels. An experimental setup similar to the original is used: inside a tube that contains vapor of mercury atoms, a voltage is applied between two electrodes (cathode and anode) that makes a current of electrons flow between them. These electrons collide with the mercury atoms that they find in their path. It is observed that for certain values of the applied voltage there are abrupt drops in the electrical intensity recorded at the anode. These falls occur when the energy of the electrons of the current is equal to the difference between two energy levels of the mercury atom