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Chemical Reaction Changes Color Over and Over
DancingFountain writes "If you have taken a college chemistry class, you may have seen this fantastic demonstration. When two clear liquids are mixed, they immediately turn yellow, and then undulate back and forth between blue-black and yellow in a mesmerizing display. Wired Science explains that the reaction, which was developed by two high school science teachers, has been rigorously studied but not fully explained."
During this period when half of those running for office are being accused of changing their mind every 15 minutes, I expect many of these jokes to be posted.
Perpetual motion is impossible. Fundamentally. Furthermore, some chemical reactions take in heat instead of giving it off. But back to the main point, perpetual motion contradicts the second law of thermodynamics, and as a consequence, if perpetual motion machines did exist, almost everything we know about physics would be wrong.
In Repressive Burma, it's not just your connection that dies. slashdot.org/comments.pl?sid=314547&cid=20819199
No.
In fact, that's the answer to all questions of the form "So, can you use X to make a perpetual motion machine?".
The magnetic stirrer under the glass doesn't run on pixie dust...
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Maybe.
Perpetual motion machines get classified on the basis of whether they claim to violate the first law of thermodynamics (conservation of energy) or the second law of thermodynamics (limits on converting heat to other forms of energy). Whether it would be possible to have a perpetual motion machine that only violated the first law, but not the second law, is a tricky question because the first law is so fundamental to our understanding of physics (including our understanding of the second law).
Not necessarily.
In the first place, physics has yet to develop a "Theory of Everything", (e.g. integrating the general relativity view on gravity with the quantum field theory view on forces between sub-atomic particles). Since there isn't yet a theory that "explains it all", it would be hard to come up with any experimental observation contradicted that theory.
Second, it's important to distinguish between violations of the first law and violations of the second law.
In the case of the first law, conservation of energy is, admittedly, pretty fundamental to the formulation of the basic laws of physics. On the other hand, suppose experimental physicists were to discover a new sub-atomic particle that continuously emitted photons. Naturally, that would require some reworking of the standard model but many of the higher level theories might well survive largely unchanged. For example, the behavior of an electron would still be accurately described by the Schrodinger equation.
In the case of the second law, the effect on established physical theories might be even smaller. Suppose, for example, scientists discovered a particular material that developed a permanent voltage gradient across it in the presence of a strong (static) magnetic field. As long as the material got colder when the voltage gradient was used to drive a current, conservation of energy (the first law) would still be valid. The only modification that would be needed to physics would be to state that the second law applies to everything except this particular material - not really a big change.
Anyway, getting back to the original question of whether this particular reaction constitutes perpetual motion, unfortunately the answer is "no". What's happening is that the reaction inhibits itself (a negative feedback loop). The reaction starts going but produces some stuff that causes the reaction to stop but then the stuff that stopped the reaction gets neutralized and the reaction can start going again - but then the reaction produces some stuff that causes it to stop again, etc.
Conservation of energy is a *VERY* well established scientific fact.
No. Conservation is a law - a postulate. Something that we're extremely certain that can't prove using other laws, but that has never, ever been wrong once. That is the fact. If we found something that violated this law, then it would no longer be considered a law. Personally, I don't consider overwhelming evidence that something has always happened a particular way within the observation of man proof that it always did or always will. Don't get me wrong: I'd never take a bet that a perpetual motion machine is going to work, but I'm not going to go around believing that reality is 100% certain to work the way that I think it does, either.
The system eventually reaches equilibrium, and the cycle stop
Apparently goes through about 10 cycles, according to Wikipedia.
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