Experiments have been carried out for half-zones of acetone (Pr = 4.3) to investigate the effects of evaporative cooling on the flow structures and temperature fields during transition from steady to oscillatory convection. The unstable flow phenomena have been measured using a variety of diagnostic techniques to determine the effects of evaporative cooling on Marangoni convection in liquid bridges of intermediate Prandtl number. The results show that Marangoni convection in acetone liquid bridges with and without strong evaporation becomes unstable due to the same mechanism but the evaporation has a strong stabilizing effect on the onset of oscillatory Marangoni convection. (c) 2006 Elsevier Ltd. All rights reserved.