Experiments were carried out to examine isotopie fractionation during the grain coarsening of snow particles soaked in water. The δ¹⁸O values of both snow and water changed with time, having a trend towards homogenization, that is the difference in the δ¹⁸O values for snow and water decreased. The results indicated that the final δ¹⁸O value of water was more negative than that of snow, corresponding to the fractionation factor between the solid and the melt. A simple model has explained the experimental data qualitatively, but modifications would have to be made before it could be used to give quantitative predictions for changes in δ¹⁸O values.