71–80 of 198 posts
I wonder if this affects photosynthesis in any way? IIRC plants are green because chlorophyll does not absorb that color. Maybe that’s partially because green light induces too much evaporation?
Photomolecular effect leading to water evaporation exceeding the thermal limit - https://news.ycombinator.com/item?id=38112574
If not a mistake or some unsustainable side reaction, this could mean cheaper things that require evaporation like desalination.
A lot of people here though are saying it means things which would violate conservation of energy.
I can't wrap my head around this story. What does it mean in thermodynamic terms? Isn't there a fixed amount of energy per mass that it takes to convert liquid water into vapor? Why does it matter that the energy comes from light?
Thermodynamics and evaporation are my day job and I think most other explanations here are missing the point. Evaporation normally occurs when individual water molecules have enough thermal energy to break their intermolecular bonds, leaving the bulk liquid and entering the air. In this case, they found strong evidence that water molecules were being removed in groups of several water molecules. Because intermolecula…
Earlier quoted context omitted.
Thermodynamics and evaporation are my day job and I think most other explanations here are missing the point. Evaporation normally occurs when individual water molecules have enough thermal energy to break their intermolecular bonds, leaving the bulk liquid and entering the air. In this case, they found strong evidence that water molecules were being removed in groups of several water molecules. Because intermolecula…
But in a closed system, the energy to boil or evaporate the same amount of water is the same right? As in, you still have to pay the energy price but evaporating all the water is probably easier engineering wise?
But it's comparing apples to oranges, because the "end product" is different. In one, you have a cloud of individual molecules. In the other, you have a cloud of molecule "clumps". If you take it further and break those clumps down to individual molecules as well, I expect the total energy input would match that of evaporating water in the normal way.
To the experts reading this, am I close?
I can't wrap my head around this story. What does it mean in thermodynamic terms? Isn't there a fixed amount of energy per mass that it takes to convert liquid water into vapor? Why does it matter that the energy comes from light?
> What does it mean in thermodynamic terms? Isn't there a fixed amount of energy per mass that it takes to convert liquid water into vapor? Yes. The rest of the energy comes from the bulk water/hydrogel in other words, the bulk water is cooled by this process. What’s happening is that energy is sloshing around between various degrees of freedom of the system (the temperature of the system is not zero). When it sloshe…
Earlier quoted context omitted.
My 8th grade understanding is evaporation doesn't always mean steam.
What exactly is the distinction between water vapor and steam?
Earlier quoted context omitted.
My 8th grade understanding is evaporation doesn't always mean steam.
What exactly is the distinction between water vapor and steam?
I can't wrap my head around this story. What does it mean in thermodynamic terms? Isn't there a fixed amount of energy per mass that it takes to convert liquid water into vapor? Why does it matter that the energy comes from light?
Thermodynamics and evaporation are my day job and I think most other explanations here are missing the point. Evaporation normally occurs when individual water molecules have enough thermal energy to break their intermolecular bonds, leaving the bulk liquid and entering the air. In this case, they found strong evidence that water molecules were being removed in groups of several water molecules. Because intermolecula…
I can't help but think of ultrasonic humidifiers/misters, which use vibration to do evaporation-adjacent kinds of things.
I also wonder if specific wavelengths of light are involved (sort of how 2.4ghz microwaves work on water)