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Coiling Instability in Honey Poured into Water by Kyle James Lueptow

Honorable - Contrived Category

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School: Evanston Township High School

Teacher: Daniel DuBrow

This photo illustrates the straight stream of high viscosity honey which curls around itself when poured into water. The honey falls in an almost perfectly straight line, but as soon as it touches the water, it twists around itself in a coiling pattern as it sinks down. The differences in density and viscosity prevent the honey and water from mixing immediately even though the two liquids are miscible, meaning that they will dissolve together eventually. The stream of honey channels through the water because the honey has a higher density and viscosity than water. This stream is stable in the air; however, when it hits the surface of the water, it becomes unstable, tending to coil as it falls through the water. This coiling instability can also be seen when pouring honey or another viscous liquid onto a solid surface -- the stream of liquid spirals around where it contacts the solid. One of the amazing things about this physical concept is that such elegant patterns occur so often, and in such mundane, everyday activities, such as pouring the honey into tea.

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