I recall one time when I was you we went camping overnight and each of us
brought a clear glass gallon of water. The jugs were left outside the tent
on the ground. That night we had a pretty good freeze. I was first up and
went to get take a leak and get a drink. I could see that the water hadn't
frozen. So I picked up a jug opened it and hoisted it to my mouth and to my
amazement the water froze in an instant. The other jug didn't. One was
city tap water and the other was from a well and I can't recall which was
which. I recall reporting the phenomena in grade 9 science and we found out
about supercooled liquids. A very interesting phenomena when you consider
that the jug that freezes nearly instantaneously has to give up a bunch of
latent heat. Since then I've seen that happen with beer thats been in the
freeze but its not as dramatic because they all do it and you can't see as
well, and there's many more other things in solution lke alcohol,etc.

--

73
Hank WD5JFR
"ve3..." wrote in message
ups.com...

Henry Kolesnik wrote:
This is a long and perhpas delerious shot but there may something called
thermal momentum a far reach but here goes. The hot water may be cooling
at
a faster rate and forgets to wait on the cold water to catch up.
"bpnjensen" wrote in message
ups.com...
ve3... wrote:
wrote:\\\

The deal with the hot water pipe freezing first is due to the lack
of
dissolved gasses in the water. That is, the heating process takes
the
dissolved gasses out of the water, which in turn makes it easier to
freeze.
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Alas, It ain't so simple. The finest scientific minds of our time have
been unable to come up with a theory that can be proved by experiment.
Current theories include:
- evaporatve cooling
-convection
-dissolved gases
-surrounding environment

snips

The key to all of these is that there is something about both fluids,
apart from temperature, that is not equal.

If you have two identical, equal water fluids whose only difference is
temperature, I would bet good money that the cold one will freeze first
- it simply has to lose a lot less energy to get to the phase change.

I think the best experiment would be not to avoid the presence of
nucleation sites, but to make sure that each vessel has a roughly equal
load of them, guaranteeing that freezing would occur as soon as
possible for each one (just like in nature, where nucleation sites are
abundant).

Bruce Jensen
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from Yahoo:
"...for such a seemingly simple substance, water is surprisingly
complex, and its behaviour is poorly understood. The Mpemba effect is
just one of 38 anamolies of H2O."

Experiments to examine any theory have to contend with an enormous
number of variables.
A paper from London South Bank University examines a few anamolies. Do
not miss "icosahedral water clusters" at the bottom of the page.
http://www.lsbu.ac.uk/water/explan.html