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Q & A: Hot Japanese tea cups?

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Most recent answer: 10/27/2012
Q:
my background is a ph.d. in electrical engineering.so, in general know about heat conduction. my question is: why do japanese tea cups conduct the heat so much faster? it is surprising since it is hard to hold a japanese cup without burning yourself and this from a culture in which drinking hot tea is a tradition. thanks peter rohr
- Peter Rohr (age 73)
Sunnyvale, CA usa
A:
Well I'm not an expert on Japanese tea cups but I can make some guesses.  As you know from V=IR and its inverse, if the resistance is low then the amount of current flow is high.  Now replace V with the temperature difference between the inside and outside of the cup and R with the thickness of the cup.  So if the cup is thin the the equivalent  R is low, the heat transfer is large and will raise the temperature of the outside of the cup.  The thickness of a standard American coffee cup is much larger than that of a delicate paper-thin Japanese variety so you don't notice the temperature difference so much.

LeeH

(published on 10/27/2012)

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