Cart
Table of Contents
Dancing Sands. When waves with the same frequency, but traveling in opposite directions, pass each other they can interfere to create standing waves. Ideally, a standing wave oscillates in a stationary envelope, with nodes, points at which wave displacement is zero, and antinodes, points where wave displacement is maximal. To create the images on the cover, a thin, square plate of metal is mounted on a wave driver and sprinkled with sand. When the frequency of the wave driver matches a resonant frequency of the metal plate, two-dimensional standing waves are established and sand particles dance away from regions where wave displacements are large to collect in nodal regions, where there is little or no movement of the plate. Sand-covered nodal curves enclose bare antinodal regions of the plate in patterns that become more complex and intricate as the driving frequency increases.
