How about this theory. the greater delta H heat flow induces structural changes in water molecule matrix that causes rearrangements that more quickly attain to the optimal ice lattice structure more quickly, and this 'enhanced crystallisation through increased delta heat' causes it to cool quicker. That this occurs in water and not other substances is related somehow to its 'paradoxical' expansion on cooling*. That the effect is flakey is related to the outsize effects of impurities and defects in the crystal lattice, and how these flaws can propagate their crystallisation inefficiencies.
Maybe a more thermodynamic way to state this is:
- temperature is an aggregate measure, so because of the nature of the ensemble, you can have some states at -22 C that still have some molecules of water (or groups of molecules of water connected by intermolecular bonds), at a higher temperature.
- when you start higher, you are going to end up with more of these higher temperature pockets in your ensemble, as your aggregate temperature drops through the degrees toward freezing
- these higher energy / "higher temperature micro regions", provide more possible microstates for the water crystals to rearrange, than if these intermolecular clumps of water were lower temp, (or were less numerous, as would be the case starting lower), and the higher temp clumps (or pockets, in the honeycomb of partially crystallized water) will probe the space of configurations of molecular arrangements more effectively (than if they were lower temperature, or less numerous, as would be the case starting lower).
- By being able to search more of the configuration space, they naturally are able to more quickly find optimal water crystal arrangements of molecules, where some H20 from the higher temp clumps, can slot into the existing lattice, or accrete onto the existing surfaces of forming ice crystals. So these ice crystals in a solution of liquid that has these higher temp pockets can be more effective at generating the movement necessary to find configurations where molecules, and clumps of molecules effectively fit together in the lattice, letting it find more effective crystal structures, leading to more efficient (and faster) crystallisation.
These other commenters are talking about the same thing:
Maybe a more thermodynamic way to state this is:
- temperature is an aggregate measure, so because of the nature of the ensemble, you can have some states at -22 C that still have some molecules of water (or groups of molecules of water connected by intermolecular bonds), at a higher temperature.
- when you start higher, you are going to end up with more of these higher temperature pockets in your ensemble, as your aggregate temperature drops through the degrees toward freezing
- these higher energy / "higher temperature micro regions", provide more possible microstates for the water crystals to rearrange, than if these intermolecular clumps of water were lower temp, (or were less numerous, as would be the case starting lower), and the higher temp clumps (or pockets, in the honeycomb of partially crystallized water) will probe the space of configurations of molecular arrangements more effectively (than if they were lower temperature, or less numerous, as would be the case starting lower).
- By being able to search more of the configuration space, they naturally are able to more quickly find optimal water crystal arrangements of molecules, where some H20 from the higher temp clumps, can slot into the existing lattice, or accrete onto the existing surfaces of forming ice crystals. So these ice crystals in a solution of liquid that has these higher temp pockets can be more effective at generating the movement necessary to find configurations where molecules, and clumps of molecules effectively fit together in the lattice, letting it find more effective crystal structures, leading to more efficient (and faster) crystallisation.
These other commenters are talking about the same thing:
- https://news.ycombinator.com/item?id=31929552
- https://news.ycombinator.com/item?id=31928942
- https://news.ycombinator.com/item?id=31929779