A Space & astronomy forum. SpaceBanter.com

Go Back   Home » SpaceBanter.com forum » Space Science » Science
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

Why is absolute zero finite compared to maximum heat (which is seemingly infinite)?



 
 
Thread Tools Display Modes
  #42  
Old January 17th 04, 07:32 PM
Gordon D. Pusch
external usenet poster
 
Posts: n/a
Default Why is absolute zero finite compared to maximum heat (which is seemingly infinite)?

"Stewart Smith" writes:

Here's an interesting aside:
Is this the beginnings of a Freeze Ray device?


No, it most certainly is =NOT=.


Molecules Knocked Cold
---------------------------------------------------------------------------
Chemists have long used supersonic gas expansions to create beams of
molecules that are "cold" in the sense that the molecules are in low
vibrational and rotational states and do not undergo collisions. However,
translational motion of the molecules still makes them "hot" in the
laboratory frame of reference,


Like most press-releases, the above is oversimplified and rather misleading.
Please note that the author has used a perverse definition of "hot," namely,
is treating coherent translational motion of the stream _AS IF_ it were "random"
thermal motion --- which it most definitely is =NOT= !!! The kinetic temperature
of a gas is defined in terms the "random" component of motion left over once
the _average_ motion of the molecules has been subtracted, i.e., it is defined
relative to the _MEAN REST FRAME_ of a parcel of gas. Treating the "bulk"
motion _AS IF_ it were "heat" only gets one into trouble, both conceptually
and physically. I will give the author "partial credit" in recognizing this
conceptual inaccuracy by putting "scare quotes" around "hot" --- but it
would have been =MUCH= better if the author had simply =NOT= made this
incorrect and conceptually misleading statement _AT ALL_, since it adds
nothing of value to the article.


-- Gordon D. Pusch

perl -e '$_ = \n"; s/NO\.//; s/SPAM\.//; print;'



 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT +1. The time now is 06:25 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 SpaceBanter.com.
The comments are property of their posters.