Stalagmometric method

The stalagmometer method is a common method for measuring the relative surface and interfacial tension.

The measurement is made on the basis of geometric computation. In the measurement, the liquid is pushed out to flow through a cannula, or a specially shaped capillary tube at the end of the droplets fall slowly. The gravimetrically or volumetrically acquired drop mass allows the calculation of the surface tension. It makes use of advantage that the resulting droplet size of a liquid is directly proportional to the surface tension at the drainer is ( γ = f · V · ρ / n). The surface tension ( γ ) is given by the flowed out volume (V ) (where a number of drop ( s) are formed ), the density ( ρ ) and a factor f, which is determined by calibration with a reference liquid having a known surface tension.