Re: States of matter was: New 'electrical active' Armour to defeat hand held anti-tank rounds

Andrae Muys schrieb:
> Scott Siebold wrote:
> >> Err... not quite. A superconductor is not a 'state of
> >> matter' in the same sense as the others. A superconductor is a
solid
> >> that happens to have no resistance to electricity. 
> > 
> > Ah yes quite. Ther are 5 "states" of matter and one of
> > those states is "superconductor". I didn't make this up but it was
in one 
> > of those 200 level	physics classes I had to take in collage. 

I usually don't like to tout my credentials, but I've got a Ph.D. in
Physics. With all due respect, I suspect your college Physics teacher
used a personal definition or was talking in a very loose manner. The
page quoted by Andrae Muys
http://www.ualberta.ca/~bderksen/florin.html
also has a discussion of 'States of matter' which summarises the
standard definition.

> > A material that is in the superconductive state "ACTS" differently
then 
> > matter in the other states.

Only with respect to how it conducts electricity and the consequences
thereof.
Things that don't change significantly as you cross the
superconductivity threshold:
- density
- color
- cristalline structure
- hardness
- heat conductivity and capacity etc.
The changes are much smaller than between solid, liquid or gas.

Greetings