Perhaps you have stood near a
wet dog as it dries by shaking its fur. Watch out! An impressive amount of water is thrown off in all directions. The shaking
technique for furry creatures including mice, dogs, and bears is studied by researchers at the Georgia Institute of Technology
in Atlanta. They find that larger animals tend to move their bodies at a frequency of 4-5 shakes per second. Mice and rats
move more rapidly, up to 27 shakes per second. Whatever the size, each creature begins the shaking process with its head and
then the process moves along the body. Mathematical formulas have been established for the animal shaking process based on
size, nature of the fur, water surface tension, and other variables. The animals apparently know these technical details by
instinct.
The findings may have application
to a variety of machines including clothes dryers, painting devices, and spin coaters. This last device is used to apply a
thin coat of liquid material on a flat surface. A droplet is applied to the surface and then rapidly rotated, causing the
droplet to spread outward. In each of these machines there are unknowns regarding the rapid fluid motion. Continued study
of animal behavior may lead to more efficient construction and operation of the machines. In clothes dryers, for example,
a rapid back-and-forth motion, similar to a shaking dog, may be more efficient than the usual spinning motion.