We present a physical model that describes the acoustic pressure pulses from diluted suspensions of metal nanospheres in a liquid medium irradiated by laser pulses. The experimental measurements of the photoacoustic signals are also reported, where the suspensions of 8-nm gold nanospheres in water at different concentrations and different temperatures were irradiated by 0.8-ns laser pulses. We mainly investigate how the nanosphere concentration and the suspension temperature influence the photoacoustic responses. The estimations from our model are found to be in good agreement with the results from the experiments. (C) 2013 Elsevier B.V. All rights reserved.