Blowing Big Bubbles

TL;DR

This paper investigates the formation of exceptionally large bubbles by gentle blowing, analyzing the effects of surfactants and air speed, revealing new regimes of bubble stability and size.

Contribution

It introduces a novel regime for creating bubbles up to ten times larger than the wand size by gentle blowing and compares the effects of different surfactants on bubble stability.

Findings

Big bubbles form at low air speeds similar to droplet dripping.

Fairy liquid bubbles detach and remain stable for seconds.

SDS bubbles tend to burst before detaching.

Abstract

Although street artists have the know-how to blow bubbles over one meter in length, the bubble width is typically determined by the size of the hoop, or wand they use. In this article we explore a regime in which, by blowing gently, we generate bubbles with radius up to ten times larger than the wand. We observe the big bubbles at lowest air speeds, analogous to the dripping mode observed in droplet formation. We also explore the impact of the surfactant chosen to stabilize the bubbles. We are able to create bubbles of comparable size using either Fairy liquid, a commercially available detergent often used by street artists, or sodium dodecyl sulfate (SDS) solutions. The bubbles obtained from Fairy liquid detach from the wand and are stable for several seconds, however those from SDS tend to burst just before detachment.