Think physics and reality. Temperature is just a measure of heat,
which is a result of molecular motion. Applying energy to some
substances causes the molecules to bounce around more: we
perceive this as heat and measure it as temperature.
Heat propagates as molecules transmit energy to other molecules
by bouncing against them, so heat conduction is limited by the
speed at which these molecules can bounce, and transmit energy to
adjacent molecules.
It's a lot slower and less efficient than shipping the energy
around as E-M radiation, to affect the target molecules directly.
Apply too much energy to any real substance and you don't get
heat transfer, you get a change in the substance: a chemical
reaction, an absorption of energy, not heat transfer.
Theoretically, you can calculate anything, but if you don't take
into account the limitations of some conductive substance, it
probably isn't heat transfer that you're calculating, just some
ideal mathematical construct unrelated to reality.
On Sat, 23 Oct 1999 16:31:28 -0400, "Bill Todd"
<billtodd at foo.mv.com> wrote:
>I'm not sure that's relevant: the *degree* to which the top-side of the
>frying pan heats up is related to the heat capacity (if I recall the term
>correctly - or perhaps it's specific heat?) of the frying pan - i.e., the
>more heat it can absorb per unit volume for a given temperature rise, the
>slower the temperature of a portion far from the heat source will rise. But
>that doesn't prohibit instantaneous propagation (which would mean that the
>far portion's temperature rise would *begin* immediately, regardless of how
>slow it was).
>>- bill
>>Steven Vogel <spamvogel at iconn.net> wrote in message
>news:38112AAB.1E02 at iconn.net...>> Naturally, you're correct. As an experiment to prove your point, you
>> could turn the burner on your stove on high. After ten minutes, put a
>> cast iron pan on the burner and put your hand on the top of pan right
>> away for ten seconds. After ten minutes, have the poster that said that
>> heat travels faster than the speed of light put their hand on the top of
>> the pan for ten seconds.
>>>> The person who doesn't scream has the better grasp of reality.
>>>> Bill Todd wrote:
>> >
>> > If heat in a substance does in fact propagate via the interaction of
>> > particles and EM fields, it's hard to see how it could do so at a speed
>> > faster than c.
>> >
>> > - bill
>> >
>> > Erik Max Francis <max at alcyone.com> wrote in message
>> > news:3810DBC3.3463B0BB at alcyone.com...>> > > Ronnie Sahlberg wrote:
>> > >
>> > > > Well actually I am, but the equation is faulty. It is only a good
>> > > > approximative model
>> > > > of the physic characteristics of heat, not an exact description of.
>> > >
>> > > Well, no kidding.
>> > >
>> > > > Examine function describing heat distribution along the string.
>> > > > Examine value of this function at t=epsilon (epsilon approaching 0)
>> > > > especially "interesting" are the values of this function infinitely
>> > > > far
>> > > > from
>> > > > point p. It is small but non-zero.
>> > >
>> > > This is doing the equation, not doing the physics.
>> > >
>> > > --
>> > > Erik Max Francis | icq 16063900 | whois mf303 | email max at alcyone.com>> > > Alcyone Systems | irc maxxon (efnet) | web
>http://www.alcyone.com/max/>> > > San Jose, CA | languages en, eo | icbm 37 20 07 N 121 53 38 W
>> > > USA | Fri 1999 Oct 22 (43%/950) | &tSftDotIotE
>> > > __
>> > > / \ Do not seek death. Death will find you.
>> > > \__/ Dag Hammarskjold
>
Thanks. Take care, Brian Inglis Calgary, Alberta, Canada
--
Brian_Inglis at CSi.com (Brian dot Inglis at SystematicSw dot ab dot ca)
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