Surface tension has long been recognized as an important physical characteristic of fluids and colloids that can affect biological processes. Scientists sought ways to measure this phenomenon, but reproducible results were difficult to obtain. Two approaches, developed to measure this subtle force, are displayed here.
The process of drop formation by liquids is, in part, controlled by the surface tension of the fluid. To determine surface tension, the stalagmometer used a drop weight method, in which the number and weight of drops were compared to those from a reference liquid. Seemingly simple, the stalagmometer nevertheless required considerable skill and absolute cleanliness for readings to be meaningful.
National Institutes of Health