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The idea of harvesting energy from graphene is controversial because it refutes physicist Richard Feynman’s well-known assertion that the thermal motion of atom
by joe_the_user 5y ago
The idea of harvesting energy from graphene is controversial because it refutes physicist Richard Feynman’s well-known assertion that the thermal motion of atoms, known as Brownian motion, cannot do work. Thibado’s team found that at room temperature the thermal motion of graphene does in fact induce an alternating current (AC) in a circuit, an achievement thought to be impossible.
Even more, the result is essentially claiming to violate the Second Law Of Thermodynamics. HN should be flagging this sort of crank claim.
- zdragnar 5y agoHow so? Isn't it just converting the effect of thermal energy to electric energy? Presumably, there is no Brownian motion at absolute zero, and the actual output would drop well above that temperature.
- fsh 5y agoA direct conversion of thermal energy into electric energy would cool down the entire system. Since electric energy carries no entropy, this would reduce the overall entropy of the system. This is forbidden by the second law of thermodynamics.
- actually_a_dog 5y agoIt's not a closed system.
- gus_massa 5y agoThe "system" is the circuit (including the graphene), a closed box around it and the gas that is inside the box.
- Rury 5y agoIf treated as a closed system, the claim would indeed be violating the second law of thermodynamics. If it's treated as an open system, then well yeah... the "limitless" energy is actually coming from outside the boundaries of the system, which they conveniently neglect to track. No magic to be had here, but a cool way to convert energy...
- wrycoder 5y agoLet them do like the inventors of the transistor: create an oscillator and drive a speaker.
- 14 5y agoIt actually covered that in the article “According to Kumar, the graphene and circuit share a symbiotic relationship. Though the thermal environment is performing work on the load resistor, the graphene and circuit are at the same temperature and heat does not flow between the two. That’s an important distinction, said Thibado, because a temperature difference between the graphene and circuit, in a circuit producing power, would contradict the second law of thermodynamics. “This means that the second law of thermodynamics is not violated, nor is there any need to argue that ‘Maxwell’s Demon’ is separating hot and cold electrons,” Thibado said.”
- gus_massa 5y agoThat part is confusing. Anyway, if you see the animation in the video, they are trying to makes a device that use this effect to collect the charge in a capacitor and then release the energy in a resistor, and that proposed device breaks the second law, in particular is more clear with this version https://en.wikipedia.org/wiki/Second_law_of_thermodynamics#Planck's_proposition https://en.wikipedia.org/wiki/Second_law_of_thermodynamics#P...
- Firmwarrior 5y agoMan, I saw this article, and I was like "Huh, that's impossible.. but it's on HN, surely it's not complete BS" turns out I just got in a little too soon.. ugh