The Floating Ball Paradox
Henry C. Wente
Contact the author: Please use for correspondence this email.
Submission date: 14. Dec. 2006
published in: Journal of mathematical fluid mechanics, 10 (2008) 4, p. 569-582
DOI number (of the published article): 10.1007/s00021-007-0251-0
MSC-Numbers: 76B45, 76D45, 74G65
Keywords and phrases: capillarity, surface tension
In capillary theory there are two kinds of surface tension. There is the surface tension at the interface between two immiscible fluids. Thomas Young (T. Young, An essay on the cohesion of fluids, Phil. Transactions Royal Society, London, 95, (1805) 65-87) also allowed for there to be a surface tension associated with a liquid-solid interface. He proceeded to use a balance of forces argument to derive the well-known contact angle condition along a liquid-liquid-solid intersection. The validity of this argument has recently been called into question by R. Finn (R. Finn, The contact angle in capillarity, Physics of Fluids 18, 047102, (2006)). A floating ball experiment discussed in that paper leads to an apparent paradox. We address this issue.
Please see also the MPI MIS preprint 154/2006 by Robert Finn.