The methodological specificity of measuring surface tension by the methods of large drop and maximum pressure in a drop

Abstract

A comparative analysis of the experimental data on the surface tension (ST) of low- melting metals, obtained by the method of maximum pressure in a drop and the method of a large drop, shows that the values of ST obtained by the large drop method for all studied metals are noticeably higher than those obtained by the method of maximum pressure in a drop. The reasons for such discrepancies, although in some cases they exceed the total errors of the ST measurement by the indicated methods, have not yet been clarified. In this regard, the paper gives a comparative analysis of the methodological specificity of measuring the surface tension by the methods of maximum pressure in a gas bubble or a drop and a lying or “large” drop. It is shown that these methods are theoretically substantiated, technically perfect, have a sufficiently high accuracy and are relatively simple. Based on the identification and critical analysis of the influence of the main factors on the measured value of the surface tension, the main reasons for the discrepancy between the experimental data on the surface tension of low-melting metals obtained by different methods are determined. It is shown that the underestimated ST values obtained by the method of maximum pressure in a droplet are due to the fact that all factors influencing the measured value of surface tension are directed towards a decrease in its value. Although the influence of each of these factors separately is insignificant, they together lead to a noticeable decrease in the value of surface tension. It is shown in the work that the method of maximum pressure in a drop, being the most accurate method for measuring ST, gives somewhat underestimated ST values for all low-melting metals.