Related to this popular question: How strong is the force of ice expanding when freezing?
We are cooling H2O to absolute zero while keeping the volume (density) constant. The answers focus on the solid portion as H2O normally expands when freezing.
But what about the liquid portion of the cooling?
We are holding overall density, but imo best to think of it as the equivalent “a chamber of set size and heat being removed”.
If we start at room pressure and temperature, during the cooling to 0C water, shouldn’t the liquid part decrease (very slightly) in density? I can’t decide whether:
Liquid would pool under a tiny mostly-vacuum with some water vapor, still almost exactly at room pressure.
Pressure would decrease until the 0C liquid density matched the 30C liquid density and water still fills chamber.
What would happen? Does presence of gravity change it? (Please be sure to consider both questions)