From: utzoo!decvax!harpo!seismo!hao!hplabs!sri-unix!KING@KESTREL
Newsgroups: net.physics
Title: adding cold milk to hot tea
Article-I.D.: sri-unix.4954
Posted: Tue Dec 28 10:03:03 1982
Received: Wed Dec 29 05:49:19 1982

From: Richard M. King <KING at KESTREL>
	The standard answer is to add the milk BEFORE answering the phone, 
because the mixture will cool slower than the tea.  I am suspicious for the
following reasons:

	1) if you don't add the milk, it will warm up.  If the temperature
of the milk is above the dew point, the milk will gain heat much faster than
would be implied by the temperature difference between the milk and the air

	2) if you add milk the fluid level in the cup increases.  This
increases the dissipating surface.

	It can be easily shown that if the dissipation of a container of fluid
is proportional to the temperature difference times the volume of fluid, than 
it doesn't matter when the milk is added when the fact that the milk would have
warmed up during the telephone call is taken into account.

							Dick
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