Re: Cooling of a Liquid Substance

Since the tablespoon of sugar is at room temperature, the temperature of
coffee will come down slightly after the sugar dissolves in it. This is
slightly offset by heat of solution which is released when sugar is
dissolved, however this is quite small.  The two effects are opposite of
each other, but the net effect is to bring the temperature of coffee
down.  Now, the rate of cooling is directly proportional to the
temperature difference between coffee and surrounding air.  Hence the
rate of cooling will drop after sugar at room temperature is added to
coffee.

--
Mukund V. Karwe
Food Science/CAFT, Rutgers University