George S. K. Wong
Inst. for Natl. Measurement Standards, Natl. Res. Council Canada, Ottawa, ON K1A 0R6, Canada
In view of the adoption of the International Temperature Scale of 1990 (ITS-90), which defines the International Celsius Temperatures, t[sub 90], the dependence on temperature of the speed of sound in pure water is examined. Drawing on the experimental data published previously [V. A. Del Grosso and C. W. Mader, ``Speed of Sound in Pure Water,'' J. Acoust. Soc. Am. 52, 1442--1446 (1972)], it is found that the change from the previous t[sub 68] scale is significant. At 100 (degrees)C, the difference between the two scales (t[sub 68]-t[sub 90]) is 0.026 (degrees)C, resulting in a difference of 0.022 m/s for the speed of sound. The speed of sound is fitted to a new fifth-order polynomial applicable over the t[sub 90] range 0--100 (degrees)C.