The Vibrations of Particles

Abstract

Consider a simple situation in which a gong is struck and heard. When the gong is struck, it moves rapidly to and fro in a fairly regular pattern; that is to say, it vibrates. The air close to the vibrating gong is alternately compressed and rarefied. The alternate compressions and rarefactions of the air are passed along through the air as wave motion, by which the pattern of to-and-fro motion travels great distances without any one portion of the substance moving very far. The wave motion sets up pressure variations at our ears, and so drives our eardrums into vibrations similar to those of the gong, but much less energetic.