New Electromagnetic Dynamometer: Measuring the Surface Tension of Liquids

Abstract

We realized an electromagnetic force sensor for measuring the surface tension of liquids by Wilhelmy plate method. The accuracy of the sensor is ∆m= 0.3 mg and referring to the force is ∆F = 3µN. the surface tension of water-ethanol systems was obtained by the accuracy of ∆σ = 0.06 dynes/cm. The operating principle of this dynamometer is based on the fundamental laws of electromagnetism (Faraday-Lenz law) and the mechanical properties of elasticity of a spring. The values obtained of the surface tension with our device are in good agreement with the results expected found in the bibliography