Abstract
Making soap bubbles by blowing air on a soap film is an enjoyable activity, yet a poorly understood phenomenon. Working either with circular bubble wands or long-lived vertical soap films having an adjustable steady state thickness, we investigate the formation of such bubbles when a gas is blown through a nozzle onto a film. We vary film size, nozzle radius, space between the film and nozzle, and gas density, and we measure the gas velocity threshold above which bubbles are formed. The response is sensitive to containment, i.e., the ratio between film and jet sizes, and dissipation in the turbulent gas jet, which is a function of the distance from the film to the nozzle. We rationalize the observed four different regimes by comparing the dynamic pressure exerted by the jet on the film and the Laplace pressure needed to create the curved surface of a bubble. This simple model allows us to account for the interplay between hydrodynamic, physicochemical, and geometrical factors.
- Received 26 August 2015
DOI:https://doi.org/10.1103/PhysRevLett.116.077801
© 2016 American Physical Society
Physics Subject Headings (PhySH)
Focus
Physics of Blowing Bubbles
Published 19 February 2016
Using a bubble-blowing apparatus, researchers developed a model that explains the effects of several factors, such as the breath velocity, on the process of blowing a bubble.
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