Rubber Bands and Energy Dissipation

1. May 21, 2006

pallidin

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. May 21, 2006

Bystander

Last edited by a moderator: May 2, 2017
3. May 21, 2006

pallidin

Thanks for your response, but links are not working for me. Maybe something on my end.

4. May 21, 2006

Bystander

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?

5. May 21, 2006

pallidin

Yes, I am getting a "cannot display page". I will take your advise and do the Google seach as you stated. Thanks.

6. May 21, 2006

pallidin

"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."

7. May 21, 2006

pallidin

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.

8. May 21, 2006

Bystander

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.