81–90 of 139 posts
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the hot thing will get cooler. like to make something clean, you have to make something else dirty.
Is that true though? If I have say a box with mixed red and blue bricks and I sort them by color, both sides are "clean" now.
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Heating and cooling are rarely nicely split up in time. While you're heating something it is also cooling and while you're cooling something it is also warming up. This usually limits your ability to heat something up or to cool it because at some point these two are in balance.
No. Put a cold thing into something hotter and the thing will heat up without cooling.
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Heating and cooling are rarely nicely split up in time. While you're heating something it is also cooling and while you're cooling something it is also warming up. This usually limits your ability to heat something up or to cool it because at some point these two are in balance.
No. Put a cold thing into something hotter and the thing will heat up without cooling.
> While no immediate practical applications exist, the researchers envision enhanced efficiency in micromotors, microscale cargo transport, and materials that can self-assemble or self-repair. Everyone who has ever written a grant application will recognise this wording.
Erm so? No tech would ever be developed or furthered without exploring possibilities. Huge swathes of process and tech is developed purely on just trying things. HNs recent anti-science propaganda is getting pretty out of hand.
It's like if you have sand and water, it's really quick to mix the two together, but waiting for them to settle requires minutes to hours.
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the hot thing will get cooler. like to make something clean, you have to make something else dirty.
Is that true though? If I have say a box with mixed red and blue bricks and I sort them by color, both sides are "clean" now.
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Exactly, I always thought heating raises the entropy of a system and cooling puts it back in the "more orderly" state. So of course it can't be symmetric. Just like breaking a wine glass, reversing that process takes a lot more effort. Of course I have no idea if the above makes any sense, it's just an "intuitive understanding" I somehow got.
My source of the same intuitive understanding; electric bills. Power to heat, waste is more heat (just not where desired?). Power to cool is used to move the state of one side of the system to another, ideally open, side. Though this does raise the question of if it's possible to cancel energy out. I think that's likely stopped by Heisenberg's uncertainty of measurements (and exactly matching them even when measured)…
The intuition is that the heat pump is moving heat, as opposed to just generating it.
The phys.org article and science paper text are both impenetrable for different reasons (though I don't blame the paper). Can anyone explain this result like I have a college degree but not in physics? I'm especially interested in what the actual difference in "microscopic" process is between heating and cooling.
They experimentally demonstrated that it takes significantly more energy to move a microparticle the same distance when cooled than the amount of energy it would take when heated.
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Microwaves penetrate the interior of objects (outside of metal) that are in their Faraday cages, leading the internal temperature of those objects to rise dramatically. Blast chillers work like reverse ovens, from the surface to the interior.
Microwaves target the resonant frequency of intermolecular hydrogen bonds and impart vibration. It's a very special mechanism that doesn't really lend itself to this sort of analogy.
I always feel a little stupid or strange reading a lot of these science headlines and introductions. I wasn't aware that people considered there to be a symmetry between heating and cooling. I thought that the entire point of thermodynamics is that they are asymmetric. Even the article mentions that it's been known that heating is more efficient than cooling.