Re: [Fis] definition(s) of order/disorder ?

Devin's classification into "symmetric" and "grouping" order deserves
attention.
Maybe it worths to be compared (then merged?) with my classes of order,
which I mentioned before in this forum:

- Atoms in a crystal are ordered (equal density), a glass is disordered
(random density within the glass) --- this is a symmetric approach (or
crsytallographic approach);
- Atoms condensed (grouped) in one corner of a box are ordered (random
density within the box), atoms of a gas filling free the full box (after
certain time) are disordered (equal density) --- (this is what I call a
thermodynamic approach, and) this may represent a grouping approach - if I
did not misunderstand his definition.

The two order-disorder concepts contradict to each other - although both
are applied in their own domains.

There are also other aspects of the classification of order/disorder,
symmetric/asymmetric relations and the arrrow of the change of entropy:
these are whether we investigate global or local (actual or potential)
processes.
[Note, local processes generally take place in open (sub)systems, where the
2nd law of thermodynamics should not be applied.]

Globally:
- in thermodynamic terms: symmetry and entropy increase, while order
decreases.
- in symmetric terms: all symmetry, order and entropy increase.

Locally:
- in thermodynamic terms: order increases, while symmetry decreases and
entropy may decrease.
- in symmetric terms: order and symmetry decrease, and entropy may also
decrease.

A conceptual paradox may appear, when we confuse "global processes
discussed in thermodynamic terms" with "local processes discussed in
symmetric terms": in these two cases the arrows of order accidentally
coincide, (this may cause the virtual confusion) although the arrows of
time differ, and the arrows of entropy may differ (and coincide with the
arrow of symmetry - as usual). In other words: in this situation we
compare and therefore can confuse the two different order concepts, that
apparently behave similarly.

Gyuri
Symmetry Festival 2003 http://www.conferences.hu/symmetry2003/
____________________________________________________
György
Darvas <mailto:>darvasg@helka.iif.hu; <mailto:>h492dar@ella.hu
                            http://www.mtakszi.iif.hu/darvas.htm
SYMMETRION http://www.geocities.com/symmetrion/ <mailto:>sym@freemail.hu
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Received on Sun May 23 16:07:17 2004