Dust Figures in a Kundt's Tube

Abstract

An experimental investigation of Kundt's tube phenomena has been performed with the primary purpose of investigating the actual motions and appearances of the striations under different conditions. No attempt was made to formulate rigorous theories explaining the figures. Very clear photographs of the particles in a striation were made by causing the striation to move out to the end of the tube and remain stationary long enough to be photographed. Photographs were also taken through the eyepiece of a microscope. From these it was evident that the particles in a striation did not, in general, touch each other. Striations on either side of a long metal rod on the bottom of the tube usually showed different spacings and occurred in different numbers on either side. This could not be caused by overtones since it is unlikely that more overtones could exist on one side than on the other. An electrostatic charge in motion near the tube prevented the figures from forming. A stationary charge in no way prevented their formation. Figures destroyed by the motion of a charge would slowly build up again when the charge was brought to rest, even with the charge present.