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Re: Dew Formation



About 20 years ago, Joe Johnson, a New York City high school
physics teacher, demonstrated the double mirror reflections
described by Bernard Cleyet, below.

He placed some dry ice at the focus of one mirror and let us
feel the temperature produced at the focus of the opposite mirror.
He explained that it is not only possible to transmit heat by
this method, but it is also possible to transmit cold.







On Mon, 15 Mar 2004 00:09:54 -0800 Bernard Cleyet <anngeorg@PACBELL.NET>
writes:
A common demo. is two large concave mirrors with a small heater at
the focus of one. A hand placed at the focus of the other, tho > ten
yards away is noticeably warmed. "My" demo. manager suggested
replacing
the heater with a container of lN2. Again noticeable and a teaching
moment.

I am preparing a long rebut. to JD's objections to Levi, et cet.
However, since here on the west coast it's midnite, late.

bc

John Denker wrote:

Quoting John Mallinckrodt <ajm@CSUPOMONA.EDU>:


I DID say 2 pi, not 4 pi.



OTOH using mirrors and such you can significantly exceed 2 pi.

=================

It might make an interesting science-fair project to see just
how cold you can make something by radiative cooling.

Impressively cold, I'll bet.







Herb Gottlieb from New York City
A friendly place to live and visit