Surface and Interfacial tension [Part-3(b)](Measurement of Surface and Interfacial tension: 3. Wilhelmy plate method 4. DuNouy ring method )

This document discusses two methods for measuring surface and interfacial tension: the Wilhelmy plate method and the DuNouy ring method. The Wilhelmy plate method involves immersing a thin plate into a liquid and measuring the force required to detach the plate from the surface. The surface tension can then be calculated based on this force measurement. The DuNouy ring method similarly uses a ring immersed at an interface and measures the force needed to detach the ring, from which the interfacial tension can be derived. Both methods relate the measured detachment force to the perimeter of the liquid/interface and surface/interfacial tension.