Re: only holds true at the very low temperatures ...
(a) "spin", as applied to subatomic particles, or atoms, isn't the same as mechanical rotation (because that is called angular momentum).
(b) the nuclear spins referred to may not be strongly coupled to the atomic motions of the molecules that (in aggregate) make up the temperature.
It /might/ be that the temperature of the water has an effect on the nuclear spins of its constituent atoms on some relevant timescale, but it isn't necessarily so.
While "rotate" is the wrong word the spins can be affected by the magnetic fields of nearby nuclei (i.e. in adjacent molecules), or even the overall motion of the water molecule itself as it moves or spins in local fields.
Biting the hand that feeds IT
