Honey, yoghurt and Runniness

When one of my children was young he would lean back after eating delicious honey laden yoghurt and say “ I love the way that trickles down my tummy” Very satisfying.
What happens and the mechanism is not one that is highlighted in Nutrition
Even the simplest ingredients can give rise to complex patterns. Mark Buchanan of the University of Oslo, Norway, and his team have tackled one family of patterns — those formed when fluids containing suspended particles flow down a vertical surface. Langmuir 23,3732-3736 (2007)
Yoghurt running down the side of a pot, for example, is cut through by vertical, branched channels, whereas honey tends to break up into wavy horizontal bands. The particle size determines which type of pattern is produced.
Smaller particles leave behind vertical channels, because the downward flow of the film becomes focused along certain paths by a feedback mechanism that amplifies flow rate. Wavy horizontal bands appear in suspensions of larger particles, as particles get trapped by random imperfections on the vertical surface and jam together to form stress bearing arches.
So I love the way that trickles down my tummy” Very satisfying.
Taken from Nature 2007, vol 446, p 587

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www.nutrition-nutritionists.com

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Martin Eastwood

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