The physics of the chocolate fountain

A mathematics student has worked out the secrets of how chocolate behaves in a chocolate fountain, showing they are models for important principles of fluid dynamics.

The study shows why the falling curtain of chocolate surprisingly pulls inwards rather than going straight downwards.

Adam Townsend, the paper’s author, likened the way chocolate behaves to water bells.

“You can build a water bell really easily in your kitchen” says Dr Helen Wilson, the other author of the paper, and supervisor of Townsend’s project. “Just fix a pen vertically under a tap with a 10p coin flat on top and you’ll see a beautiful bell-shaped fountain of water.

“Both the chocolate fountain and water bell experiments … allow us to demonstrate several aspects of fluid dynamics, both Newtonian and non-Newtonian,” she said.

“It’s serious maths applied to a fun problem.” continues Adam Townsend. “I’ve been talking about it at mathematics enrichment events around London for the last few years. If I can convince just one person that maths is more than Pythagoras’ Theorem, I’ll have succeeded. Of course, the same mathematics has a wide use in many other important industries – but none of them are quite as tasty as chocolate.”

The study is published in the European Journal of Physics.

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