Factors Affecting the Frequency Produced by Resonating Bamboo Tubes

Abstract (EN)

Bamboo has been used to make flute-like instruments for millennium. While the formation of standing waves in rigid cylindrical tubes is well understood, bamboo tubes are typically neither completely rigid nor cylindrical, leading to the possibility that sound produced might diverge from theoretical predictions. The frequency of sound produced from bamboo tubes with one open end was therefore studied. Bamboo tubes of different length, radius, and hole position with respect to the tube mouth were prepared. The rim of each of the tubes was tapped with a metal rod and the resonant sound analysed. First, the effect of the length of the bamboo tube on the frequency produced was investigated for tubes ranging in length from 15 to 30 cm. The result showed that the longer the tube, the lower the frequency, matching the theory for a cylindrical tube. Next, the effect of the position at which a hole is drilled in the tube on the frequency was studied, with holes drilled at positions ranging from 5 to 25 cm away from the tube’s mouth. The results showed that the further the hole was from the mouth, the higher the frequency. Lastly, the effect of the radius of the tube was observed and showed that the bigger the tube, the lower the frequency, and the higher the period, following the theoretical prediction.