Downloaded By: [Quéré, David] At: 22:19 20 November 2007 Bouncing Bubbles Fre ´de ´ ric Vincent Anne Le Goff Guillaume Lagubeau David Que ´re ´ Physique et Me ´canique des Milieux He ´te ´roge `nes, UMR 7636 du CNRS, ESPCI, Paris, France We discuss here soap bubbles hitting a bath of water and bouncing off the surface. We first describe the characteristics of this event, that is, the bubble deformation during impact and the contact time associated with the rebound. Then we propose a tentative scenario for understanding this behavior, which stresses the impor- tance of the transient film of air between the bubble and the bath, preventing the coalescence from taking place. Keywords: Non-wetting; soap bubbles 1. INTRODUCTION Adhesion and wetting are fields closely related to each other [1]. If two solid plates stuck together with a liquid glue are separated, a crack can propagate either along the solid (adhesive failure) or within the liquid (cohesive failure). In the first case, the minimum energy required for propagating the crack arises from the creation of solid=vapor and liquid=vapor interfaces and suppression of a solid=liquid frontier, while cohesive failure just implies the creation of two liquid=vapor interfaces. Hence the latter scenario will be favored if the liquid totally wets the considered solid. Conversely, a zero-wetting situation will induce a non-adhesive behavior. Such a Received 10 April 2007; in final form 21 August 2007. One of a Collection of papers honoring Liliane Le ´ger, the recipient in February 2007 of The Adhesion Society Award for Excellence in Adhesion Science, Sponsored by 3M. Address correspondence to David Que ´re ´, Physique et Me ´canique des Milieux He ´te ´roge `nes, UMR 7636 du CNRS, ESPCI, 10 rue Vauquelin, Paris F-75005, France. E-mail: david.quere@ESPCI.fr The Journal of Adhesion, 83:897–906, 2007 Copyright # Taylor & Francis Group, LLC ISSN: 0021-8464 print=1545-5823 online DOI: 10.1080/00218460701699765 897