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                          PlanetPhysics
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The PlanetPhysics Newsletter

Edition #2
March 24th, 2006
www.planetphysics.org

Contents

*  Historical:  Works by Einstein, Planck and Fourier
*  Mechanics:   Centre of Mass
*  EM:          Loop Example of Biot-Savart Law
*  Thermo:      Heat
*  World Edit:  Entropy
*  Feedback:    Comments and Questions

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In the months since the last newsletter, PlanetPhysics has 
started a new initiative to electronically preserve historical 
works in physics.  Entries have begun on works by Einstein, 
Fourier and Planck and are described below.  Our ability to make 
this happen hinges on two things.  First, all works produced in 
the United States before 1923 are in the public domain, therefore 
we are within our rights to copy and distribute them on 
PlanetPhysics.  Secondly, the old-school monk like dedication of 
patrons is needed to manually copy these works into the LaTeX 
format.  This may sound absurd in today's high tech world, but 
without money for fancy OCR equipment we must use the advantage 
of working together to make sure these works remain free to the 
world.  You may think this goal is a waste a time, but keep in 
mind one thing.  Powers at be *cough* Google *cough* and other 
libraries are quickly digitizing a large number of works and 
there is no guarantee that the digital copies of public domain
works, which are now copyrighted by the digitizers, will be 
freely available to the world.  In the extreme, original works 
will become more scarce and digitizers will hold the keys to 
these momentous works.  One last advantage is these works will be
search-able and connected to entries within PlanetPhysics.  
You can help by

1) Finding public domain works and making them available to 
   others to help with the copying (i.e., upload them as books as
   images, pdf, etc.)

2) Copy, Copy, Copy, but stay within legal copyright laws

3) Proofread entries

Note that a good source of pre 1923 books may be your local 
library. 


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** Works by Einstein, Planck and Fourier **

The first few sections have been added for the works:

1) "Relativity: The Special and General Theory" by Albert Einstein
    http://planetphysics.org/encyclopedia/SpecialTheoryOfRelativity.html

2) "The Theory of Heat Radiation" by Max Planck
    http://planetphysics.org/?op=getobj&from=objects&name=TheoryOfHeatRadiation

3) "The Analytical Theory of Heat" by Joseph Fourier
    http://planetphysics.org/encyclopedia/AnalyticalTheoryOfHeat.html
  

** Centre of Mass **

"The centre of mass of an object is a point in space where, for 
many purposes, the mass of the object may be assumed to be 
concentrated. For example, an object hung from a string in a 
uniform gravitational field will have its centre of mass straight 
below the string. The centre of mass can be used in many other 
ways to simplify a complicated system by treating it as a point 
particle..."

http://planetphysics.org/?op=getobj&from=objects&id=96

** Loop Example of Biot-Savart Law **

"Here we will examine two examples of the Biot-Savart law, one 
simple and the other more challenging. To begin we will find the 
magnetic field at the center of a current carrying loop as shown 
in figure 1..."

http://planetphysics.org/encyclopedia/LoopExampleOfBiotSavartLaw.html

** Heat **

"Heat is one of the many forms of energy in the universe around 
us. It is the measure of how much energy is transferred between 
objects due to either temperature differences or emitted 
radiation. Since heat is energy, the SI unit is the joule.

In order to visualize heat, one must understand a little about 
the underlying mechanisms of heat transfer. This means that the 
definition of heat encompasses three ways of energy transfer: 
heat conduction, convection and radiation..."

http://planetphysics.org/encyclopedia/Heat.html

** Entropy **

"Entropy has a long and rich histroy in physics and was developed
by many scientists over the years including Clausius, Maxwell, 
Boltzmann, Planck, Gibbs, Pauling and more recently Shannon and 
Hawking. The applications of entropy are far and wide ranging 
from engines to black holes. The concept of entropy was 
introduced by the German R. J. E. Clausius in 1854..."

Note that anyone can edit the entropy article, so please help 
improve it.
 
http://planetphysics.org/encyclopedia/Entropy.html

** Feedback and Comments **

Please let us know how you like the text only version of the 
newsletter.  Of course we are considering something more flashy,
but do not know if it is worth the time, yet.

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