Nanoparticles have been produced by laser ablation of thin gold films on soda lime glass slides that are immersed in distilled and deionized water. The size of the nanoparticles, as determined by fitting the UV-vis absorption spectrum, shows that the average particle radius depends on the thin film thickness in the range of 50-200 nm. A heuristic model is developed to explain these results as being strongly dependent on the average temperature that is reached in the thin films, and the subsequent heating of the surrounding medium. The strong thermal mismatch at the film-substrate boundary appears to play a strong role as well. (C) 2013 Elsevier B.V. All rights reserved.