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2nd law exception

  1. Dec 21, 2003 #1
    in this link someone claims an increase
    in order that is against the 2nd law

    http://news.bbc.co.uk/1/hi/sci/tech/2135779.stm

    is a 1/10 sec time frame valid or just random chance
    anyone got a better link to this

    I found this pdf
    http://rsc.anu.edu.au/~evans/papers/exptFT.pdf

    on this short a timescale it seams to me that
    brownian motion or random chance is driving the results
     
    Last edited: Dec 21, 2003
  2. jcsd
  3. Dec 21, 2003 #2

    Bystander

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    Dennis Evans does NOT leap to wild conclusions; that said, his forte is the theoretical, and "there's many a slip twixt the cup and lip" --- or, twixt the theoretical result and the lab bench. The pdf is barely legible on my screen --- the BBC "science desk" butcher job description of the experiment leaves a lot to be desired, but it's a fairly decent bet that experimental artifacts have been missed in the analysis/correlation of theory and experiment. Stay tuned for critique of the paper --- provided I survive the eyestrain --- holidays and all, it'll be mid-Jan before I get my hands on P. Rev..

    Bottom line? The theoreticians strike again --- the only thing on this earth more dangerous than "a second lieutenant with a map" (pre-GPS joke for all you technos out there) is a theoretician with a test tube. The Second Law is safe --- you'll see a retraction or correction within a year --- most probably based on an analysis of the experimental design --- the "unmixing" of cake mixes has been studied to death, and this looks very much like an alternate demonstration of "unmixing" phenomena.
     
  4. Dec 21, 2003 #3

    russ_watters

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    I agree with the first part but not the second part. My gut tells me that the article misrepresented (overstated/misunderstood) the findings of the experiment. That happens all the time and is NEVER retracted.
     
  5. Dec 21, 2003 #4
    It is my understanding that parts of a system can go toward order, so long as the net movement is toward disorder. Is my understanding flawed???

    Maybe they have defined their system without the inclusion of outside energy???

    Nautica
     
  6. Dec 22, 2003 #5

    Ivan Seeking

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    The 2nd Law: "Beads of doubt"

    http://news.bbc.co.uk/1/hi/sci/tech/2135779.stm
     
  7. Dec 22, 2003 #6
    you missed a bit!

    Your posting caught my eye, so I read the link... But you missed out the important bit:


    This Second Law of Thermodynamics says that the disorder of the Universe can only increase in time, but the equations of classical and quantum mechanics, the laws that govern the behaviour of the very small, are time reversible.

    A few years ago, a tentative theoretical solution to this paradox was proposed - the so-called Fluctuation Theorem - stating that the chances of the Second Law being violated increases as the system in question gets smaller.

    This means that at human scales, the Second Law dominates and machines only ever run in one direction. However, when working at molecular scales and over extremely short periods of time, things can take place in either direction.

    Now, scientists have demonstrated that principle experimentally.




    So no change then, the 2nd law remains true above the scale of the very very small. Four gas molecules in a box CAN all move to the same side of the box still, but 1 mole of gas molecules won't.
     
  8. Dec 22, 2003 #7

    Bystander

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    Could someone please move/lock/append this to the earlier post in Class. Phys., "2nd law exception?"
     
  9. Dec 22, 2003 #8

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    The experiment looks to be an attempt to reproduce molecular dynamic or monte carlo results on the benchtop; the actual apparatus design is a very low power acoustic/vibration damper. What has actually been measured is the acoustic relaxation time of a suspended sediment.
     
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