Physics of Wet Dog
Entry posted by SwagDragon15
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We have all seen those slow motion captures of a canine mid-shake, but lets delve deeper for a moment and look at it from the point of view of a true physicist. :banghead) In this blog I will explain the concepts of Andrew Dickerson's book titled "The Wet Dog Shake," in which he, along with Georgia Institute of Technology scientists, attempt to determine the optimum speed at which dogs should shake to most effectively dry their fur. The team actually constructed a mathematical model of the processes involved, and the first realization they had to come to was that the surface tension between the water and the dogs hair is what keeps the animal wet. In turn, a centripetal force which exceeds it is required to overcome said tension. They determined, knowing that A=mv^2/r, that the frequency of the oscillation at which the dog rotates is R0.5. They then filmed multiple breeds and determined the frequency of each, with their final test subject being the Labrador retriever, with a frequency of 4.3 Hz. This, as compared to smaller animals, is much, MUCH slower. Take for example the frequency of a mouse's oscillations, at 27 Hz. This means that the bigger the animal, the slower it can shake to dry itself. The final difference which they have yet to correctly account for is the fur....but enjoy the adorable video! :wave)
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