The velocity of sound in a gas depends on its temperature, molar mass, and [lambda] = C[subscript p]/C[subscript v], ratio (heat capacity at a constant pressure to heat capacity at constant volume). The [lambda] values for air, oxygen, nitrogen, argon, and carbon dioxide were determined by measuring the velocity of the sound through the gases at room temperature. The sound velocity is measured with a microphone using Calculator-Based Laboratory (CBL) Technology. (Contains 2 figures and 1 table.)