You can get a tremendous temperature increase by rubbing plastic or wood on your jeans, easily enough to burn one's leg under the rubbing area, or enough to melt plastic. I can also nearly burn (perhaps 120 F from the feel of it; I haven't used a thermometer yet) my hands if I rub them together vigorously enough. I wouldn't attribute that to circulation increase!
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Down with categorical imperative!
flutzpah@yahoo.com
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________________________________
From: John Clement <clement@hal-pc.org>
To: Forum for Physics Educators <phys-l@carnot.physics.buffalo.edu>
Sent: Thu, January 28, 2010 4:18:23 PM
Subject: Re: [Phys-l] heat/energy
The hand rubbing is a convincing demo even if it is a cheat. Most of the
warm feeling probably comes from increased circulation. But students never
think of that. So the transfer of kinetic energy to thermal is something
they actually already understand.