This movie clearly illustrates the remarkable and fascinating interplay of acoustics, standing waves, and combustion. Chladni’s classical experiment uses a fixed plate on which a handful of grains is uniformly sprinkled. A stretched violin string is plucked along 1 edge which sets up a standing wave in the plate which causes the grains to line up along the modes. Ruben’s classical experiment provides a 1 dimensional perspective in which flammable gas is introduced into a pipe with a series of equidistant vents running along one side. Igniting the gas produces an array of flames, not especially interesting in itself, until an acoustic vibration is introduced. When a tone is played in the tube, the gas inside is set into vibration and, with the right geometry and frequency, can resonate, forming standing waves. The motion of the gas and the shape of the acoustic waves is visible in the flames. The flames reach maximum amplitude on anti-nodal points.