Du Noüy ring method
The du Noüy ring method is one technique by which the surface tension of a liquid can be measured. The method involves slowly lifting a ring, often made of platinum, from the surface of a liquid. The force, , required to raise the ring from the liquid's surface is measured and related to the liquid's surface tension, :
where is the radius of the inner ring of the liquid film pulled and is the radius of the outer ring of the liquid film.
- Butt, Hans-Jürgen; Graf, Karlheinz; Kappl, Michael (2003). "Physics and Chemistry of Interfaces". pp. 14–15.
- du Noüy, Pierre Lecomte (1925). "An Interfacial Tensiometer for Universal Use". The Journal of General Physiology 7 (5): 625–633. doi:10.1085/jgp.7.5.625.
- Papers of Pierre Lecomte du Noüy, 1883-1972
- Movie showing a du Noüy tensiometer
- Picture of a du Noüy tensiometer (National Institutes of Health)
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