What changes will happen to a bowl of ice and water kept at exactly zero degree Celsius?

Fresh water cooled to zero (0) degree Celsius and subjected to additional loss of heat energy normally will freeze. A mixture of fresh water and ice has an equilibrium temperature of zero (0) degree Celsius. Adding heat to the mixture causes ice to melt whereas removing heat causes water to freeze. For that reason, 0 (zero) degree Celsius is called the freezing point of fresh water. Cloud droplets can cool well below the usual freezing point while remaining liquid. Such cloud droplets are composed of super cooled water.