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Re: [Phys-l] Good Questions



At 01:34 PM 10/10/2006, Jim K., you wrote:
Hewitt has an overhead with this question on it.
Heat flow is proportional to delta T. If you wait to put the cream in
your coffee delta T is large for ten minutes allowing a fast flow of
heat. If you put the cream in right away delta T becomes smaller and
the amount of heat flow is much less for ten minutes.

Jim Krider Laboratory Coordinator Senior


On the other hand, and for the sake of discussion:
If you allow your hot coffee to cool for ten minutes before
creaming it, it loses a fraction of its thermal energy by evaporation.
If you cream it immediately, the evaporation is suppressed by the
oily film, and its improved surface thermal resistivity reduces
the coffee convection plume too, a double whammy.....
(??? Experiment rules!)


Brian Whatcott Altus OK Eureka!