Convection and Dissolved Gases

Hot water develops stronger convection currents. The large temperature gap between the water and the freezer walls drives faster circulation, carrying warm water to the edges where it loses heat quickly.

Heating also drives out dissolved gases like oxygen and carbon dioxide. Some researchers think degassed water freezes more readily, while the gases trapped in cold water may interfere with ice crystal formation. Neither idea alone is enough, but together they chip away at the paradox.