Re: Physics. (looks funny but it's only physics !!!)

[quk@isham-research.demon.co.uk (Phil Payne)]

In message <c=US%a=_%p=Lucent_Holmdel%l=HO/PCLANHO/00305170@hoexch.lucent.com> mamirkalali@lucent.com writes:

> Interesting question (however impractical it may be to measure anything
> from water dumped out of an airplane !!!?)

Yup.

> First of all, water dumped from an airplane does not get "atomized" as
> in "single atoms". "Atomizers', as used in the perfume industry, only
> chop the liquid in smaller chunks. Therefore, nothing fancy happens to
> the smaller chunks of water dropping from the airplane. They may freeze
> FASTER due the change in the heat transfer characteristics but the same
> number of calories will have to be removed in order to freeze the water
> when you add them all together.

Most folks would think the cold water would freeze first.

However - what is supposed to happen (as you say) is that the water
gets "chopped up into small chunks".  How small are the chunks?

It turns out that it takes energy to form chunks, because of surface
tension.  The smaller the chunks, the more energy - T/r.

So the warmer the water, the smaller the chunks.  Thereafter,
mathematics (ratio of surface to volume) and conventional physics
(Newton's Law of Cooling) takes over.  The warmer water forms smaller
droplets, and freezes first.

If you started with the idea that the cold water would freeze first,
you'd be surprised.  Just like the Torsen - there's an effect most
people wouldn't allow for.

--
 Phil Payne
 Phone: 0385 302803   Fax: 01536 723021
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