Experiments with an Electrically Operated Kundt Tube

An experimental investigation of the striations in a Kundt tube was carried out, using an electrically driven source of sound. Thus was produced by modern equipment, consisting of an audio frequency oscillator, amplifier, and reproducing unit, details concerning which follow in the paper. Spacing between striations was found to depend on particle size. Particles in striations were observed to be repelled from each other and did not touch. All striations tested showed electrostatic effects, with strong negative charges exhibited by cork dust and positive by powdered magnesium. Standing waves in the air in a tube are shown to produce a pattern on the surface of a ribbon of liquid located in a trough along the bottom. Photographs substantiating the above statements are included in the paper.