Vacuum cleaner isolates over 12 harmonics in the corrugated whistling tube

摘要

A vacuum cleaner is used to isolate over twelve harmonics in a corrugated toy whistling tube. The toy tube is first taped along a horizontal surface. Then a vacuum cleaner with a hose diameter approximately the same as that for the toy tube is turned on. As the vacuum cleaner hose approaches one end of the corrugated tube, individual higher harmonics are generated. From a sound recording, the frequencies of the harmonics can be measured with the free audio program Audacity and found to agree with theory to about 1%. An exciting class demonstration is included with a video accompanying this paper: Ruiz M J 2020 Video: Vacuum cleaner isolates over 12 harmonics in a corrugated whistling tube (http://mjtruiz.com/ped/hummer/).