Abstract: We demonstrate a photoacoustic method for measurement of sound speed in solid medium.The pulsed photoacoustic signals generated on the surface of a solid medium are muti-reflected by the opposite interfaces of the medium,and it results in a photoacoustic pulses sequence.We calculate the transmitting time of sound between the opposite interfaces of the medium from the measured muti-reflected photoacoustic signals.The sound speed is computed with the measured transmitting time and the width of the object.This method is experimentally verified on a brass cylinder and an aluminum plate.This measurement method is suitable for experimental teaching for undergraduates in physics.

Key words: pulsed laser, photoacoustic, sound speed