The speed of sound in an unknown material can be easily measured using a 208. time-of-flight' technique with 2 transducers. if you send out a pulse whose start time to you know, and measure the arrival time tarivai of the transmitted pulse through a measured length /of a sample of the unknown material, then the speed of sound is: c/(tarrivalto), assuming plane wave propagation in one dimension. for the mean values of length / and arrival time tarrival taken from a series of n 50 measurements each, with instrument resolutions b and sample standard deviations s, mean 2 cm b 0.1 cm s 0.15 cm n 50 (tarrival- to)mean 5.7 microseconds b, 0.1 microseconds s-0.25 microseconds nt 50 ine the mean sound speed cmean and the combined standard uncertainty in sound determ speed ue