A simple apparatus was constructed for an undergraduate physical chemistry laboratory to determine a mathematical model of wavelike motion. The apparatus was assembled by attaching an airflow valve connected to a tank of argon gas to a GC column, thus creating regulated airflow. The air was manipulated to gently flow over a small sensitive microphone that was attached to an inexpensive resonator. A model will be developed to measure the speed of sound that will lead to the measurement of the molar mass.