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26 December 2010

Feline Fluid Dynamics

For the Middle Primary class, which is interested in water:

In the online edition of Science Magazine for 11 November 2010, you can read a paper titled "How Cats Lap: Water Uptake by Felis catus", written by scientists at MIT, Virginia Tech and Princeton University. Here's the abstract (summary):

"Animals have developed a range of drinking strategies depending on physiological and environmental constraints. Vertebrates with incomplete cheeks use their tongue to drink; the most common example is the lapping of cats and dogs. We show that the domestic cat (Felis catus) laps by a subtle mechanism based on water adhesion to the dorsal side of the tongue. A combined experimental and theoretical analysis reveals that Felis catus exploits fluid inertia to defeat gravity and pull liquid into the mouth. This competition between inertia and gravity sets the lapping frequency and yields a prediction for the dependence of frequency on animal mass. Measurements of lapping frequency across the family Felidae support this prediction, which suggests that the lapping mechanism is conserved among felines." (link)

Many journals and newspapers have picked up this story (Science Daily, MIT's news release, The Los Angeles Times) - click on any of these links to read a more popular description of the findings.

You can also see the videos on YouTube that show what the scientists are talking about.







It is said that cats drink this way so that they don't get their chins wet, whereas dogs do use their tongues like ladles, with some splashing.



Having watched the videos, and read the research, can you analyze how you drink water from a fountain, or a faucet? Do you use the cat method, or the dog method?  Is there a way to improve? Can you make a video of how you drink?


Original source: Massachusetts Institute of Technology, Department of Civil and Environmental Engineering. "Cats show perfect balance even in their lapping." ScienceDaily 12 November 2010. 26 December 2010 .