Una misurazione elettrolitica della carica dell’elettrone

A simple electrolytic experiment suited to students’ practical work allows to find an approximate value for the charge of the electron in a relatively short time and without having to make sensitive direct measurements of mass with 1 mg scales, not easily found in school labs. Electric current is passed through a copper sulphate solution with cylindrical copper wires as electrodes. The students measure the loss of mass by the anode from the reduction of its thickness, measured with easily available 0.01 micrometers. Although the computer uncertainties are about 100%, the mean result found by the students is very close to the official value and the mean spread is only about ±15%.