A quite extraordinary demonstration of quantum electrodynamics

A bubble chamber picture of part of an electromagnetic shower demonstrates many interesting phenomena, including the existence of antimatter, the materialization of a high energy photon into an electron-positron pair, the emission of radiation by accelerating charges, and the Compton effect. This article introduces the subject of particle physics, explaining in particular the role of the bubble chamber, and it carefully describes the parts of the picture that demonstrate the phenomena of interest. Some relevant kinematics are given in an appendix. (author)