Abstract

This paper examines the historical back­ ground leading to the discovery of the Mach reflection effect and applies original documents from Mach’s residue which are kept in the archives of the Ernst-Mach-Institut in Freiburg. Two experimental setups for the generation and demonstration of the Mach reflection effect, incorporating an overhead projector, are described: Mach’s historic mechanical shock wave reflection and interaction experiments with soot covered glass plates, performed in 1875. The Mach triple points sharply erase the soot which results in a residual picture of funnel-shaped V-formations. The head-on collision of two shock waves is marked as a narrow line of piled-up soot. Caltech’s hydraulic jump reflection experiments in a shallow ripple tank, performed during World War II. Regular reflection and its transition into a Mach reflection wave. Using a slightly inclined tank and providing a “shoreline” in the middle of the tank, Mach stem propagation slows down to zero when hitting the shore line and, therefore, can be observed “live” without the use of a slow-motion technique.