2. Voltage and surface energy – Equivalence

For solid surfaces, readers can consult the article [M 1 425] , which describes surfaces using three approaches: crystallographic, physical and thermodynamic. The article also deals with industrial surfaces and their practical characterization. As for liquid surfaces, the subject of this article, we begin by defining surface tension and showing its equivalence with surface energy.

Consider a thin sheet of soapy water (width $\mathcal{l}$...