1. Electron in matter

The electron is an elementary particle that carries the negative charge quantum – e. Due to the very high intensity of electrostatic forces compared to gravitational attraction, a charged particle is immediately shielded by other charged or at least polarized particles before recombining and disappearing. Quantities of free electrons are created in our environment by the disintegration of cosmic rays; their existence is demonstrated by fog chambers in which an atmosphere of super-cooled alcohol vapour condenses as a particle passes by.

The Greek scientist Thales de Millet was the first to demonstrate electrical phenomena, obtaining electrons through triboelectricity by rubbing amber. In fact, it was the Greek word eλeχτρoν, amber, that gave its name to the elementary particle essentially...