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 wrote= : > These "jiggling things" are very interesting. On that video Feynman claim= s > that when you tie some paper together with a rubber band particles inside > keep "jiggling" as long as you keep it like that (except that rubber does > 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 wrote: >> > >> >> 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 --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .