jcims 12 days ago

It almost certainly doesn't violate our understanding of thermodynamics, but it's not clear that it would have to in order to condense ambient water vapor from the atmosphere.

From the paper [1]:

Remarkably, when these amphiphilic nanoporous PINFs are exposed to high yet subsaturating conditions [i.e., relative humidity (RH) < 100%], macroscopic water droplets appear spontaneously on the film surfaces without the need for cooling, as illustrated in Fig. 1C and shown in Fig. 1D.

1 - https://www.science.org/doi/10.1126/sciadv.adu8349

2
BenjiWiebe 12 days ago

Well, when water changes from vapor to liquid, it releases heat. The heat has to go somewhere.

Sorry, I don't know the correct physics lingo. Heat of enthalpy or formation or whatever.

chasd00 12 days ago

Tangent but this may solve a mystery of mine. When I make scrambled eggs I add a little bit of water to make them fluffy. When I turn off the heat there’s a puff of steam I can’t explain. Since it seems to me more heat is needed to produce that extra puff of steam. However, maybe the fast condensing of the water vapor that happens when I turn off the stove produces a. I start of extra heat and therefore the steam?

jcims 12 days ago

Is it gas stovetop?

If so, it could be that the water vapor coming from the eggs no longer mixing with the hot gases coming from the flame around the pan, allowing it to drop below the dew temp (?) and allowing it to condense right above the pan. IOW the water vapor is always there, you just can't see it until it is able to condense in lower ambient temps.

BenjiWiebe 12 days ago

I don't think the fast condensing of steam would cause enough heat to cause more steam, though. Because the reason it condenses fast is because there's heat being removed from the system (cooling to the room, and no longer more heat getting added). So the heat is already "spoken for" - it's the reason that steam turned back into water.

The other commenter that wonders if it's a gas stove might be onto something.

abracadaniel 12 days ago

Maybe the drop in temp stops a Leidenfrost effect that was reducing the surface area of the food that was contacting the pan.

jcims 12 days ago

Sure, but it could get absorbed/radiated away in the base material.

wrp 12 days ago

If water vapor is condensing on the material, wouldn't there be a transfer of heat energy?

pyinstallwoes 12 days ago

Heat transfer is not transfer of heat energy