An instrument and its utilization are described which provides for study of several aspects of sound waves. Basically the instrument consists of a pair of telescoping plastic tubes. The inner tube has one end closed by a removable plug containing a built-in microphone. A speaker whose diameter conforms to that of the outer tube is driven by an audio oscillator.O-ring seals are used to confine the major portion of the sound energy inside the tubes. Acoustical phenomena observable include: closed and open-tube resonance, longitudinal nature of sound waves and limitations of mechanical resonance of particles such as cork dust, use of Lissajous figures to observe phase variation of wave as a function of distance from source and to locate resonance positions with increased precision, excitation of various modes of vibration and analysis thereof with a frequency counter, and absorption of sound energy.