I think that when the rubber band is stretched, the individual atoms inside the molecules have less freedom to "jiggle" and need to do so in a lesser amount of ways than when the molecules are un-stretched. It may be similar to when a gas is compressed. Its molecules get closer and collide a lot more. Isaac Em 9/9/2012 17:08, Sean Breheny escreveu: > Yes, but they jiggle regardless of whether the band is stretched or > not so I don't see how the jiggling provides any means of energy > storage (other than normal thermal energy storage). > > Sean > > > On Sat, Sep 8, 2012 at 11:02 PM, Paul Anderson wrote= : >> But they do jiggle faster and slower, depending on the temperature. >> >> -------- >> Paul Anderson -- VE3HOP >> >> On 2012-09-08, at 7:45 PM, Sean Breheny wrote: >> >>> I think he is just talking about the thermal vibration of the >>> molecules in the material. They are jiggling all the time, regardless >>> of whether the rubber is stretched or not. His point is that the >>> jiggling tends to kink the long-chain molecules so that their natural >>> (at rest) length is shorter than their max possible (un-kinked) >>> length. >>> >>> Sean >>> >>> >>> On Sat, Sep 8, 2012 at 3:09 PM, Tamas Rudnai w= rote: >>>> These "jiggling things" are very interesting. On that video Feynman cl= aims >>>> that when you tie some paper together with a rubber band particles ins= ide >>>> keep "jiggling" as long as you keep it like that (except that rubber d= oes >>>> not last forever). It seems to me that it is a very good way to store >>>> energy for a longer period of time. >>>> >>>> Tamas >>>> >>>> >>>> On 8 September 2012 10:51, Sean Breheny wrote: >>>> >>>>> Thanks! I had not found such a simple explanation before! >>>>> >>>>> On Sat, Sep 8, 2012 at 11:53 AM, Peter Johansson >>>>> wrote: >>>>>> On Sat, Sep 8, 2012 at 3:23 AM, Sean Breheny wrot= e: >>>>>> >>>>>>> A long time ago I noticed that a rubber band feels cool after it is >>>>>>> stretched and released. >>>>>> The physics, as described by Feynman: >>>>>> >>>>>> http://www.youtube.com/watch?v=3DXRxAn2DRzgI >>>>>> >>>>>> -p. >>>>>> -- >>>>>> http://www.piclist.com PIC/SX FAQ & list archive >>>>>> View/change your membership options at >>>>>> http://mailman.mit.edu/mailman/listinfo/piclist >>>>> -- >>>>> http://www.piclist.com PIC/SX FAQ & list archive >>>>> View/change your membership options at >>>>> http://mailman.mit.edu/mailman/listinfo/piclist >>>>> >>>> >>>> >>>> -- >>>> int main() { char *a,*s,*q; printf(s=3D"int main() { char *a,*s,*q; >>>> printf(s=3D%s%s%s, q=3D%s%s%s%s,s,q,q,a=3D%s%s%s%s,q,q,q,a,a,q); }", >>>> q=3D"\"",s,q,q,a=3D"\\",q,q,q,a,a,q); } >>>> -- >>>> http://www.piclist.com PIC/SX FAQ & list archive >>>> View/change your membership options at >>>> http://mailman.mit.edu/mailman/listinfo/piclist >>> -- >>> http://www.piclist.com PIC/SX FAQ & list archive >>> View/change your membership options at >>> http://mailman.mit.edu/mailman/listinfo/piclist >> -- >> http://www.piclist.com PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .