Improvements in the surface tension measurement using the capillary rise method and its application to water under external magnetic fields

Abstract

Using a micro ruler and charge-coupled device image acquisition system, we have improved the capillary rise method for an easy, quick and accurate measurement of liquid surface tension. We have determined and assessed the surface tension coefficients and temperature characteristics of purified water, ethylene glycol and anhydrous ethanol. Our results demonstrate low uncertainties for stable liquids and good linearity with temperature, with a measuring percentage deviation of less than 0.1% at 20 °C for purified water. Furthermore, we exposed purified water to a series of external magnetic fields ranging from 0 to 5 T for 40 min, followed by a withdrawal of fields for 5 min and observed a drop peak of surface tension at 1.0 T and a saturating transition at approximately 1.2 T. Furthermore, we found that the surface tension coefficients rapidly decrease with increasing magnetic fields from 0 to 1.0 T, increase rapidly from 1.0 to 1.2 T and then increase slowly at fields higher than 1.2 T. The maximum reduction of surface tension affected by external fields is approximately 11%. These magnetic behaviours of water surface tension have scientific significance in the study of water molecular liquids and their potential applications in water treatments.