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Science Friday: The Fun Physics of the Wet-Dog Shake

When most of us see a wet dog about to shake himself dry, we run in the other direction. But scientists who wrote a paper...

Maria Goodavage  |  Oct 22nd 2010


When most of us see a wet dog about to shake himself dry, we run in the other direction. But scientists who wrote a paper published in the latest edition of Fluid Dynamics stayed nice and close, and filmed dogs with high-speed cameras so they would end up with quality slow-motion videos of them. They did the same for mice and rats. The purpose: To see the mechanics behind the shake, and the optimal shake speed for drying off.

We know dogs are smart, but the physics behind their shaking should qualify them for Nobel prizes

When slowed down, the wet-dog shake looks like a fancy spin cycle of a washing machine. It’s really something to behold (see the video, above). What these clever dogs are doing is breaking the surface tension between the hair and the water. The larger the animal — up to a point — the slower the shake. There’s all kinds of physics behind this, and it’s amazing that dogs who never took advanced math or physics can manage to dry off. But dogs are just naturally geniuses, it seems.

My favorite part of the video above is the Lab’s mouth. The clip starts around 2:06. Go dog, go! Those are some seriously wavy jowls!

For a little more on the science, check out Wired.com, or see the paper’s abstract on the Fluid Dynamics site. For a little less on the science, check out this highly entertaining Discovery Channel video on the wet-dog shake.