Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site lanl.ARPA Path: utzoo!watmath!clyde!burl!ulysses!allegra!bellcore!decvax!genrad!panda!talcott!harvard!seismo!cmcl2!lanl!jlg From: jlg@lanl.ARPA Newsgroups: net.sci Subject: Re: Interesting seminar Message-ID: <23051@lanl.ARPA> Date: Fri, 8-Mar-85 16:49:42 EST Article-I.D.: lanl.23051 Posted: Fri Mar 8 16:49:42 1985 Date-Received: Mon, 11-Mar-85 05:37:38 EST References: <319@boulder.UUCP> <396@cybvax0.UUCP> Sender: newsreader@lanl.ARPA Distribution: net Organization: Los Alamos National Laboratory Lines: 23 > > THINGS we learned was how to walk on 1600-2000 degree (F) HOT coals IN OUR > > BARE FEET! The POSSIBILITIES and OPTIONS that this one act releases in an > > individual are absolutely awesome! To put the POWER and WORTH of this > > Wow, I can't think of how many times I've needed to walk on hot coals! :-) > There is a short article in the March issue of Science 85 on how fire-walking > works, prompted by this fad. Essentially, there are a few physical reasons > why: coals have a very low specific heat and are very poor conductors of > heat, and moisture in the skin vaporizes which provides an insulating layer > of steam and dry skin which also conducts heat poorly. It was pointed out > that a real test of mental powers would be to walk across aluminum heated > as hot. Not at all. The same boundary layer occurs. The Scientific American article some years back recommended heating the backs of shovels for this experiment. The author of the article had walked across 12 (I think) shovels heated to 1500 degrees F. Be careful if you try this though, the boundary layer is not properly effective at LOWER temperatures (<1100 degrees). At higher temperatures, the boundary layer is not effective either, but you'll melt your shovels if you go too high anyway. J. Giles