Is it true that hot water freezes faster than water at room temperature?
Quirkie Nov 30th, 2004 There are at least five effects that contribute to hot water freezing faster. 1) Evaporation. Some of the hot water evaporates, leaving less water left to freeze. 2) Supercooling. Hot water is more likely to get supercooled below the freezing point. The hotter water near the walls of the hot container keeps the cool water away from nucleation points where the freezing process begins. Supercooled water then freezes faster. 3) Convection. Once the cold water freezes on the surface, it makes an insulating layer against further freezing. But as the hot water cools it sinks setting up currents which stir the liquid as it begins to freeze, cooling it quicker. 4) Dissolved Gases. Dissolved gases lower the freezing point below zero. Heating water drives out the dissolved gases so it freezes at a higher temperature than the cold water. 5) Conduction. When placing a object in a freezer, the hot container will melt ice under it, making a better contact with the cold surface
