the surface tension of water is an 
 important parameter for many 
 biological or industrial processes , and roughly a factor of 3 higher 
 than that of nonpolar liquids such as oils , which is usually attributed 
 to hydrogen bonding and dipolar interactions . 
 here we show by studying 
 the formation of water drops that the surface tension of a freshly 
 created water surface is even higher ( 90 mn m1 ) than under equilibrium conditions ( 72 mn m1 ) with a relaxation process occurring on a long time scale ( 1 
 ms ) . 
 dynamic adsorption effects of protons or hydroxides may be at 
 the origin of this dynamic surface tension . 
 however , changing the 
 ph does not significantly change the dynamic surface tension . 
 it also 
 seems unlikely that hydrogen bonding or dipole orientation effects 
 play any role at the relatively long time scale probed in the experiments .