title: Topological changes in a two-dimensional foam cluster.
abstract: Experiments on a small cluster of bubbles in a nominally two-dimensional foam show an instability in which a topological change forces one of the bubbles to be ejected to the outside of the cluster at a point where this is not predicted by a two-dimensional model of a foam. This is interpreted in terms of the energy of the initial and ejected states and of the finite liquid content of the experimental system. A description of the distribution of liquid in various experimental set-ups suggests that the exact response may depend critically upon the type of system used. This is demonstrated experimentally with reference to small clusters of bubbles undergoing a single topological change.
authors.affiliation: Physics Department, Trinity College, Dublin 2, Ireland. simon.cox@tcd.ie
authors.forename: S J
authors.initials: SJ
authors.lastname: Cox
authors.forename: M F
authors.initials: MF
authors.lastname: Vaz
authors.forename: D
authors.initials: D
authors.lastname: Weaire