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Re: Freezing Water



At 09:13 12/29/98 +0200, you wrote:
Yes, from time to time we talk about whether cool water or warm water
freezes "faster". Surely by now there is an FAQ somewhere. Could kind soul
please lead me to it or the like.


See http://hermes.astro.washington.edu/faq/physics/hot_water.html .

Ari.Hamalainen@Helsinki.FI

This FAQ on water freezing is something of a physics embarassment to
general science in my outsider's view.

It is well-written.
It is rigorous.
It is founded on experimentally derived data.
A Nobel physicist would not have written it in a substantially
different way, one supposes.

The reason for my embarrassment is because there is no acknowledgement
of an experimental design feature that any beginning botanist knows
by heart.

Here is the scenario, as starkly as I can put it:
We will suppose there is a striking observation, and preliminary
research indicates there are five causal factors responsible in
some degree. How can you establish the strength of these factors?

You COULD run an experiment holding four of five factors at a time and
varying the chosen variable against a control - say ten setups repeated
say five times.

The botanist wouldn't do it this way.
He might run 15 or 20 setups (as against your 50) and get better,
stronger conclusions....
He would vary several variables at the same time.

There are so many causes for variability in his life, he has developed
the tools to deal with it effectively.
In general, physics has not done this.
It seems to me, physicists should know about the methods.

Sincerely

Brian
brian whatcott <inet@intellisys.net>
Altus OK