Tuesday, November 16, 2010

Making a better washing-machine . . . courtesy of animals?

I'm amused to read of experiments being conducted at the Georgia Institute of Technology. Care2 reports:

As a child, have you ever watched a dog shaking off water and tried to imitate him? If so, you learned quickly, humans need a good towel!

A team of graduate students at the School of Mechanical Engineering of Georgia Institute of Technology, headed by Andrew Dickerson, studied the wet-dog shake. Bio-inspired design uses the mechanics of nature to understand and create. It led this group of students to investigate oscillatory shaking -- the wet-dog shake -- to see if it could be applied to make a more efficient washing machine.

With a high speed video camera, they recorded various mammals shaking off water. What they discovered was: the bigger the mammal, the shorter the shake. Grizzly bears and large dogs shake at about 4 Hz, or four shakes per second. Small animals like mice shake at 27 Hz, or 27 shakes per second. X-ray cinematography was also utilized for a look on the inside.

Video recording showed the shake starts at the head and works down to the tail. The head can twist more, creating a solid starting point for an energy wave to travel the entire length of the animal's body. But the skin moves faster than the head or body -- think of a whip. It is integral to how the animal shakes off water.

There's more at the link. Care2 also posted this video of various animals shaking themselves dry, complete with scientific measurements. It's amusing to see the difference - and, even more, the similarities - between a tiny mouse and (near the end of the video) a grizzly bear. Seems like Nature has standardized the shake across species!


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