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From: gv@hou2e.UUCP (A.VANNUCCI)
Newsgroups: net.physics
Subject: Re: A question about physics and NOT metaphysics
Message-ID: <589@hou2e.UUCP>
Date: Mon, 20-May-85 10:52:58 EDT
Article-I.D.: hou2e.589
Posted: Mon May 20 10:52:58 1985
Date-Received: Tue, 21-May-85 07:22:08 EDT
References: <111@gtss.UUCP>, <574@hou2e.UUCP>
Organization: AT&T Bell Labs, Holmdel NJ
Lines: 46


  In a previous posting I wrote:

>   From the book "University Chemistry" by Bruce H. Mahan, (c) 1969 by
> Addison Wesley.
> 
> "  Section 3.7
> 
> 	According to the law of Dulong and Petit, the heat capacity of one
> gram atom of a solid element is approximately 6.3 cal/deg.  We have seen
> that the application of this rule is not limited to elements, for
> experiments show that the heat capacity of many solids, elemental or
> compound, is 6 cal/deg *per mole of atoms*.  Of course, there are
> exceptions to this law. There are many substances whose heat capacities,
> measured at room temperature, are much smaller than predicted.  These
> exceptional substances are high-melting crystals that are made up of light
> atoms, such as boron, carbon and berillyum. Moreover, the Dulong and Petit
> law fails for all substances if the heat capacity is measured at low
> temperatures.  That is, the heat capacity of a solid is not constant, but
> increases with increasing temperature. At the absolute zero of temperature
> the heat capacity of all substances is zero. As the temperature is raised,
> the heat capacity increases, but at different rates for different 
> substances. Finally, in the limit of very high temperatures, the heat
> capacity of all solids is 6.3 cal/deg *per mole of atoms*.
> 
> 	The key to understanding the temperature dependence of the heat
> capacities of solids was supplied by Einstein in 1905....."
> 
> 
> 	Indeed, that is the work for which Einstein received the Nobel
> prize.  It turns out that the departure from the Dulong and Petit law
> at low temperatures is a quantum-mechanical effect and played a key
> role in the development of Quantum Mechanics.

  I doublechecked my statement about Einstein's Nobel prize and I
found that I made a mistake.  The Encyclopaedia Britannica says that
Einstein's 1921 Nobel Prize was for "services to theoretical physics,
especially the discovery of the law of the photoelectric effect".

  I would like to thank those who sent me mail pointing out this
mistake.

		Giovanni Vannucci
		AT&T Bell Laboratories      HOH R-207
		Holmdel, NJ 07733
		hou2e!gv