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…
Light Induced Nano Aerosolization Everything needs an acronym.
How many Libraries of Congress full of water is this?
I love seeing insane units like this in the press. Dishwashers, giraffes, bowling balls, etc. Americans will measure in anything but the metric system.
One such measure stands out to me - they described the accuracy of some computer hardware as “missing one blade of grass while mowing a lawn the size of a football field flying from a helicopter over mile up in the air” (paraphrasing and using quotes to demarcate the interesting bit; not a literal quote).
I guess it’s effective and memorable because even months later, I remember the gist of the accuracy claim (though not the hardware item name)
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?
Yes, that’s exactly right! Although I would caveat that and say that we don’t know whether it is actually useful engineering-wise.
'clumped vapor' might be way more effective for cloudseeding
> it evaporates much, much more quickly than you'd expect from purely energy per mass From purely "thermal" energy per unit mass. But the light is delivering energy too; the total energy per unit mass being delivered is still the same, it's just being put in in a different form. Nothing about this changes the bonding energy between water molecules that has to be overcome for evaporation to occur. It's just a differen…
The paper is accounting for the energy that the light is delivering. The very neat thing about this paper is that it does change the bonding energy between water molecules that has to be overcome for evaporation to occur. They observed evaporation of clusters of molecules, not individual molecules. Since whole groups of molecules are flung into the air, not all of the intermolecular bonds need to be broken for them t…
> They observed evaporation of clusters of molecules, not individual molecules. Since whole groups of molecules are flung into the air, not all of the intermolecular bonds need to be broken for them to evaporate. Heat from the air is later used to break those clusters apart into individual molecules.
This sounds more like the light is making thin fog, not water vapor.
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?
Speaking as an person ignorant of this entire field, it seems to me that if it's the case that groups of molecules are breaking off rather than individual ones, the total energy required would be less. 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 thos…
Sounds good to me. Energy is a function of state, so if you start and end with the same state, it'll require the same amount of energy. If it takes less light to knock loose bigger clumps, it'll take additional energy from somewhere else to break them up. The remainder will probably come from thermal energy from the air and water, but you could also use something like a laser or chemical reaction.
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?
Speaking as an person ignorant of this entire field, it seems to me that if it's the case that groups of molecules are breaking off rather than individual ones, the total energy required would be less. 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 thos…
You’re thinking about it right if you’re zoomed into the surface of the water plus a few millimeters above it. But the molecule clusters themselves evaporate after that, which pulls heat from the air.