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ERIC Number: EJ814867
Record Type: Journal
Publication Date: 2008-Nov
Pages: 3
Abstractor: As Provided
Reference Count: 12
ISSN: ISSN-0021-9584
Laser Measurement of the Speed of Sound in Gases: A Novel Approach to Determining Heat Capacity Ratios and Gas Composition
Baum, J. Clayton; Compton, R. N.; Feigerle, Charles S.
Journal of Chemical Education, v85 n11 p1565-1567 Nov 2008
The speed of sound is measured in several gases using a pulsed laser to create a micro-spark on a carbon rod and a microphone connected to a digital oscilloscope to measure the time-of-flight of the resulting shockwave over a known distance. These data are used to calculate the heat capacity ratios (C[subscript p]/C[subscript V]) of the gases and the composition of a binary mixture of gases. The application of lasers to the measurement of gas properties provides students with a simple, accurate, and direct, state-of-the-art method for obtaining thermodynamic data. As demonstrated for CCl[subscript 4] in nitrogen gas, the method is capable of determining the vapor pressure of a liquid-vapor equilibrium in another gas. (Contains 3 figures and 2 tables.)
Division of Chemical Education of the American Chemical Society. Subscription Department, P.O. Box 1267, Bellmawr, NJ 08099-1267. Tel: 800-691-9846; Tel: 856-931-5825; Fax: 856-931-4115; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Descriptive
Education Level: Higher Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A