RESONANCE METHOD FOR MEASURING THE RATIO OF THE SPECIFIC HEATS OF A GAS, Cp/Cv: PART I

Abstract

This paper contains the description with theory of a modification of Assmann's method for determining [Formula: see text], the ratio of the specific heats of a gas. The gas is enclosed in two chambers formed by the ends of a cylinder and a steel piston in the middle of the cylinder. This piston is caused to oscillate by an alternating current applied in coils outside the cylinder, thus subjecting the gas to alternate compression and rarefaction. The system has a natural frequency depending on the constants of the apparatus and the value of γ peculiar to the gas. The frequency of the a-c. current is varied, the amplitude of the motion of the piston observed, and the frequency for resonance measured. From this frequency and the constants of the apparatus the value of γ is determined. The method yields results of great accuracy and reproducibility.