Du Noüy ring method

This technique was proposed by Pierre Lecomte du Noüy in 1925.

Earlier, torsion wire balances were commonly used.

The method involves slowly lifting a ring, often made of platinum, from the surface of a liquid.

[3][4] The maximum force is used for the calculations, and empirically determined correction factors are required to remove the effect caused by the finite diameter of the ring: with f being the correction factor.

[5] The surface tension and correction factors are expressed by where γ is surface tension, R is the average radius of the ring, and f is correction factor.

H. H. Zuidema and George W. Waters introduced the following correction factor in 1961:[3] where C. Huh and S. G. Mason[6][7] described the correction factors as a function of

William Draper Harkins and Hubert F. Jordan[8][9] tabulated the correction factors as a function of

Close up of the ring drawn out of the liquid
A classical torsion wire-based du Noüy ring tensiometer. The arrow on the left points to the ring itself.