[cdt-l] Black pot = increased heat
kborski at yahoo.com
Wed Dec 27 17:14:48 CST 2006
Thermal energy is transferred by three methods,
convection, conduction and radiation. Heating a pot
of water with a flame is by conduction, not by
radiation. Am I right?
It is confusing. I know all objects give off
radiation and absorb radiation depending on their
temperature and composition.
I'm no physicist, but I think that, theoretically, a
black pot should both emit and absorb thermal energy
at a faster rate than a lighter colored pot. I.e., it
should cool off and heat up faster.
This from Wickipedia:
"Shiny materials typically reflect heat, just as they
reflect visible light; dark materials typically absorb
heat, just as they absorb visible light. In actuality,
light is another a form of electromagnetic radiation
with a shorter wavelength (and therefore a higher
frequency) than heat radiation. The difference between
visible light and radiant heat is small: they are
simply different "colors" of electromagnetic
I don't have any idea why Mark's test did not work
out, except that perhaps this effect is negligible on
a small pot of water. Very interesting.
> Mark Dixon <mkdixon1 at excite.com> wrote:
> I've always wondered why a blackened pot would
> increase heat transfer when cooking. Nocona said it
> in the last post. Since a stove emits long-wave
> radiation, the color of the pot should have no
> effect. If you were somehow able to cook with direct
> sunlight, shortwave radiation, a black pot would
> matter. Is the black stuff acting as an insulating
> layer? Any physicists out there to explain?
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