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Rubber Bands and Energy Dissipation

  1. May 21, 2006 #1
    Greetings all...

    When I pull a fairly good size/quality rubber band and then quickly hold it against my lips, I feel it to be quite hot.
    I assume that some of the energy used in stretching the rubber band is converted into heat by virtue of the properties of a "rubber band"

    My question is this: Is this energy "loss" appreciable? That is(speaking hypothetically), if I pull with 10 lbs of force, is 1 pound of force converted into heat? Or is this conversion a real but "negligible" factor(much less than 1-lb in my hypothetical scenario)

    Thank you.
  2. jcsd
  3. May 21, 2006 #2


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  4. May 21, 2006 #3
    Thanks for your response, but links are not working for me. Maybe something on my end.
  5. May 21, 2006 #4


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    Google "thermodynamics of a rubber band" and look at items 1 and 14. They're both PDF files, and for who knows what reason that's a function of my versions of Windows and IE, my ISP's software, and PF software, PDF links won't parse, and "insert link" doesn't seem to have done the trick --- you got "cannot display page" I presume?
  6. May 21, 2006 #5
    Yes, I am getting a "cannot display page". I will take your advise and do the Google seach as you stated. Thanks.
  7. May 21, 2006 #6
    "A related interesting property which makes a nice demonstration is to
    stretch a rubber band with a weight and heat it with a hair dryer. The
    length of the rubber band will decrease, unlike most materials which would
    lengthen, I.e. expand, when heated."

    From: http://www.newton.dep.anl.gov/askasci/gen99/gen99976.htm
  8. May 21, 2006 #7
    OK, I guess I'm asking this: With an event of "stretching" a rubber band, some amount of force is converted to radiated IR.
    Is there a "percentile" qoutient? Is it 10%, 1%, .001%, etc...
    Granted, it depends on the experiment. But surely there is some qualitative value with respect to this.
  9. May 21, 2006 #8


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    Not "force," energy, the integral of force times displacement.

    In principle, the heat loss from the rubber band can be restricted to zero; this is part of "the ideal rubber band." So, no.

    Qualitative? Yes, the rubber band is going to lose heat to the environment at a rate determined by thermal conductivity of materials in contact with it, the emissivities of surroundings, and this all gets back to comparisons of idealized adiabatic processes with real processes --- you can approach ideality in this case with insulation and radiation shields. What you then observe is a rubber band, the temperature of which is a reproducible function of elongation.
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