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Re: experimental latent heat of evaporation



My high school students were able to measure the latent heat of
vaporization of water to be 527 calories/gram. This is only a 2.4%
error from the standard 540 cal.g.

It was done in a covered, styrofoam cup partially filled with water.
Steam at 100 degrees C was added by a rubber hose from a standard
laboratory
steam generator.

If anyone wishes to have a copy of the detailed procedure and typical
student
data, send me a stamped return envelope for a complete print-out.

Herb Gottlieb
5630 229 Street
Bayside, NY 11364








On Mon, 27 Sep 2004 23:20:31 -0400 Ludwik Kowalski
<kowalskil@MAIL.MONTCLAIR.EDU> writes:
Prompted by good comments I went to the school laboratory this
afternoon and attempted to measure L. Unfortunately, my results
fluctuated widely and I have no idea why. The average result from 8
attempts was 1344 J/gram (instead of 2260); the smallest value was
800
and the largest was 3030. The method I "invented" is straight
forward;
it has probably been used by others. Expecting critical comments I
will
post a short description of the method tomorrow. Perhaps those who
are
familiar with thermal measurements will help me.
Ludwik Kowalski




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