Ice Pop

Engineers, biologists and geologists are all fascinated by freezing – watching how cold spreads along metal girders, through blood or tissue, or perhaps over mountains and glaciers. Freezing bubbles present a different challenge, as cold travels differently around their domes. This soap bubble is sitting on a bed of ice in a room chilled to around —18 degrees Celsius. Running top left to bottom right here, a temperature ‘front’ steadily moves up the bubble – known as Marangoni flow – flaking away ice crystals in a ‘snow globe’ pattern before the bubble frosts up altogether. Bubbles attempting to freeze in warmer surroundings can’t conduct temperature in the same way and eventually collapse. As bubbles are an essential part of drug-carrying emulsions, such insights may suggest more efficient forms of storage for longer-lasting drug compounds.

Written by John Ankers

John Ankers

Writer

A former researcher in systems biology, John is now an online biology tutor and professional coach supporting the wellbeing of scientists and NHS professionals. He's writing, too, of course.

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• Image from work by S. Farzad Ahmadi and colleagues
• Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA, USA
• Image originally published under a Creative Commons Licence (BY 4.0)
• Published in Nature Communications, June 2019