What Are Simple Methods to Measure Surface Tension at Home?

[Mantaray]

What would be the best way to find the surface tension of a water-based solution with an experiment without using any expensive/specialist equipment?

I thought that using the capillary rise method would be a pretty good idea as it isn't too hard to measure the variables needed to calculate the surface tension. Height and density are all quite easily measured. The contact angle is a bit harder though, or can I assume that the contact angle for this solution with a glass capillary will be 0 degrees (total wetting)?

Or I could build a balance and then measure the momentum required to lift a thin metal ring from the solution's surface. This probably isn't a really viable idea though, as the force required to lift the ring would be in the order of magnitude of mN or even smaller.

What would be a better option?

 

[Andy Resnick]

Hanging drop/sessile drop is the easiest- all you need is a photo.

http://face-kyowa.com/en/learning/learning2.html

DuNuoy ring/Wilhelmy plate-type measurements can be done on commercial equipment, but it's expensive/not simple.

http://www.attension.com/interfacial-tension.aspx

Adamson's "Physical Chemistry of Surfaces" lists about 20 ways to measure the interfacial energy. Some are pretty far out there (colliding jets, for example)- it's worthwhile checking your library for a copy.