4 ms·

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 evaporatin

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?

klysm 3y ago
(armchair science) it seems like if a bigger bunch breaks off, you get better heat transfer from the increased surface area and it would evaporate much faster. Probably the same energy price but much more rapidly applied
elil17 3y ago
Yes, that’s exactly right! Although I would caveat that and say that we don’t know whether it is actually useful engineering-wise.
- depereo 3y ago
  'clumped vapor' might be way more effective for cloudseeding
  - elil17 3y ago
    Yes, although the molecule clusters evaporate rapidly after they leave the surface
    - gpm 3y ago
      Even if they're in a high humidity environment where you could plausibly seed a cloud in the first place?
      - elil17 3y ago
        Thinking about this again, and I'm not sure. On one hand, yes, you could theoretically see a situation where the clusters want to grow because there are so many water molecules around them. But normally we seed clouds with much, much larger aerosols. Larger diameter = different (more favorable, I believe) surface energy.
JohnFen 3y ago
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 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?
- itishappy 3y ago
  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.
- elil17 3y ago
  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.
  - JohnFen 3y ago
    Gotcha. That heat from the air is also energy input that has to be counted, so it still would equal out in the end, right?
    - elil17 3y ago
      Exactly
      - JohnFen 3y ago
        So a good analogy might be that it's like a tiny version of what happens in an atomizer. It takes more energy to evaporate water than to turn the same amount of water into a very fine mist. The droplets will then evaporate on their own, using an amount of energy equal to the difference between evaporation and misting. Thank you, I've got a little clearer view of my world.

klysm 3y ago

(armchair science) it seems like if a bigger bunch breaks off, you get better heat transfer from the increased surface area and it would evaporate much faster. Probably the same energy price but much more rapidly applied

elil17 3y ago

Yes, that’s exactly right! Although I would caveat that and say that we don’t know whether it is actually useful engineering-wise.

depereo 3y ago
'clumped vapor' might be way more effective for cloudseeding
- elil17 3y ago
  Yes, although the molecule clusters evaporate rapidly after they leave the surface
  - gpm 3y ago
    Even if they're in a high humidity environment where you could plausibly seed a cloud in the first place?
    - elil17 3y ago
      Thinking about this again, and I'm not sure. On one hand, yes, you could theoretically see a situation where the clusters want to grow because there are so many water molecules around them. But normally we seed clouds with much, much larger aerosols. Larger diameter = different (more favorable, I believe) surface energy.

JohnFen 3y ago

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 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?

itishappy 3y ago
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.
elil17 3y ago
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.
- JohnFen 3y ago
  Gotcha. That heat from the air is also energy input that has to be counted, so it still would equal out in the end, right?
  - elil17 3y ago
    Exactly
    - JohnFen 3y ago
      So a good analogy might be that it's like a tiny version of what happens in an atomizer. It takes more energy to evaporate water than to turn the same amount of water into a very fine mist. The droplets will then evaporate on their own, using an amount of energy equal to the difference between evaporation and misting. Thank you, I've got a little clearer view of my world.