Development of an Educational Experiment Setup for Measuring the Speed of Sound

摘要

Sound wave cannot be seen. It is difficult to measure the speed of sound wave directly. The purpose of this study was to design and develop an educational experiment setup for measuring the speed of sound in air at a fixed pressure by the resonance method, which a surface of water will be used in reflecting sound wave from a function generator to produce resonance, which will be detected by human ear. In this study, wavelength of sound in air tube of pipe was adjusted by changing of water level. The water level was controlled with submersible pump and the gravity. The experimental data were statistically analysed by means and percentage errors. The range of percentage errors compared between the experimental value on 5 different frequencies and the theoretical value of the speed of sound is 0.07 to 0.32. This finding indicates that this experiment setup's efficiency is adequate for demonstration that the speed of sound in air can be measured by the resonance method and the sound wave with different frequencies travel at the same speed. Measurement of the speed of sound can be performed accurately and easily even though its production cost was so low with using the least experimental tools.