Figure 1

Relative deviation of experimental surface tension of water from the IAPWS-equation in the supercooled regime.

All data sets labeled “2015” were taken from ref. 2, where they were listed with the same labels: h-1, h-2, p-1, and p-2. The “h 2014” data set was taken from ref. 1, where it was referred to as the “Prague set.” All “h” sets were obtained using the capillary rise method, which is also referred to as the height method^1,2. All “p” sets were obtained using the counter-pressure method². The horizontal bars is the error bar (σ_Hru) published by Hruby^1,2 and the vertical lines is the error bar (σ_ind) calculated assuming the five datasets are independent. The agreement between the five sets of data is significantly better than the deviations from the IAPWS correlation, suggesting a systematic deviation arising as temperature decreases.