I do not think that this thought experiment works with springs. That is because spring energy is stored into compression of electron orbitals into higher energy levels. This means that compressed spring is more massive due to E=mc². However this is very intriguing thought experiment, because on the other hand crystal structure of the spring is chancing when cooled. What happens to the potential energy then? Like David said, tracking energy conservation is very tricky.
Other perhaps even more intriguing thought experiment would be that if compressed spring is assembled using molecular assembler such as star trek replicator. This should not take any more energy than with uncompressed spring, because van der waals forces are taking care of the assembling process in both cases. That is, the extra energy needed to assemble compressed spring is provided by van der waals force and van der waals force is not classical force, but it is inherent quantum property of atoms. This way we could utilize van der waals force to violate classical thermodynamics and create useful energy out of nothing. (Geckos are masters of utilizing van der waals forces) However, even if this thought experiment does not work with springs, for sure this thought experiment is working with permanent magnets. If neodymium magnet is demagnetized when attached to refrigerator door, we are loosing quite significant amount of classical potential energy that was required to remove magnet from refrigerator door. That is way more than that 360 millijoules that is the quantum energy stored into magnetic field. —Jouni On 7 September 2012 04:16, Harry Veeder <[email protected]> wrote: > If a spring is compressed by a force at room temperature, the spring > will return to its original length once the force is removed. > In the language of CoE the compressed spring is said to "store" the > energy of the work done by the force. > > Now compress the spring again and then place it in a bath of liquid > nitrogen. The spring will not return to its original length once the > force is removed. > At this stage I would say some of the "stored energy" has vanished and > CoE has been violated. > > > Harry > >
