Formal Report on Heat Capacity Ratios of Gases

Essay by THE EnigmaCollege, UndergraduateA, July 2007

download word file, 16 pages 3.4

Downloaded 76 times

Formal Report on Heat Capacity Ratios of Gases


This report discusses an investigation of the heat capacities of Helium, Nitrogen, and Carbon Dioxide. To accurately determine experimental values for the heat capacity of each gas, the heat capacity ratio was calculated from measurements of the speed of sound in each gas. An apparatus designed to measure the wavelength and frequency of sound waves in each gas was used to determine the speed of sound as a frequency was passed through each gas. The apparatus consisted of a Kundt's tube, an osilliscope, a ruler, an audio oscillator, and a frequency counter. The experimental values of heat capacity were found to agree with the theoretical values within the range of uncertainty. This experiment conclusively demonstrated an accurate method of determining the heat capacity of a gas.


To determine the heat capacity of a gas, one can first determine the heat capacity ratio,( via the speed of sound through that gas.

One can have an intuitive grasp of the fact that heat capacity varies from substance to substance based upon this relationship. If two kids are playing around at the railroad tracks they can perform a very simple demonstration of the speed of sound through different media. If one kid stands at a position of considerable distance along the tracks from the other and simultaneously screams as he hits the tracks with a hammer, the observer will notice that he can hear the sound from the hammer on the tracks before he hears the scream. This is because the metal in the railroad tracks has a higher heat capacity than air. For a substance, if the molecular mass, the speed of sound through that substance, and temperature of a gas is known, the relationship between them can yield a ratio which...