2004/11/30 by Dominic Vella, L. Mahadevan · 11 citations
Chemistry · Materials Science · Physics and Astronomy · #Electrostatics and Colloid Interactions #Micro and Nano Robotics #Pickering emulsions and particle stabilization #cond-mat.soft #physics.flu-dyn
paper · pdf · doi:10.1119/1.1898523
published as Am. J. Phys., 73 (9), pp. 817-825 (2005) · 10 pages, 12 figures. (Typos in eqs 7 and 8 corrected)
openalex publication_date 2005/08/16 · arxiv created 2007/06/25 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Objects that float at the interface between a liquid and a gas interact because of interfacial deformation and the effect of gravity. We highlight the crucial role of buoyancy in this interaction, which, for small particles, prevails over the capillary suction that often is assumed to be the dominant effect. We emphasize this point using a simple classroom demonstration, and then derive the physical conditions leading to mutual attraction or repulsion. We also quantify the force of interaction in particular instances and present a simple dynamical model of this interaction. The results obtained from this model are validated by comparison to experimental results for the mutual attraction of two identical spherical particles. We consider some of the applications of the effect that can be found in nature and the laboratory.