Re: cooling water

["Richard W. Tarara" <rtarara@saintmarys.edu>]

The various references that have been given on this topic all lead to the
same ultimate conclusion.  If you put _equal masses_ of hot and cold water
in the freezer, you will end up with a smaller mass of ice from the hot
water.  Under the right conditions, this hot water may well freeze before
the cold, but to end up with equal masses of ice, then simple Calorimetry
will dictate that the hot source will take longer than the cold.  To do
this, you'd have to start with more hot than cold since evaporation seems a
major component in the process.

So your experiment needs to precisely measure the masses both before and
after freezing.

rwt

-----Original Message-----
From: LUDWIK KOWALSKI <KOWALSKIL@alpha.montclair.edu>


> The issue of "hot water freezing faster" can be resolved by an experiment.
> Put a glass of 50 C water into a freezer and measure the time it takes
> Put a glass of 30 C water into a freezer and measure the time it takes
> to reach the temperature of -1 C, for example. Then do the same with
> 5 C wate, under identical conditions. A CBL thermistor could be used to
> monitor the temperature from outside. My prediction is that it will take
> longer when the initial temperature is higher. But I am ready to rething
> to rethink this if the experiments show I am wrong.