Nature follows rules and obeys the laws of physics, including the behavior of substances during phase changes. When it comes to water turning into ice, there are a few factors at play that prevent it from happening instantly as the temperature is lowered indefinitely. These factors include:
Heat Transfer: Cooling water requires the removal of heat energy from the water molecules. Heat transfer occurs through conduction, convection, and radiation. As the temperature drops, heat transfer becomes slower, and it takes time for the water to lose sufficient heat to reach its freezing point.
Nucleation: Nucleation is the process by which ice crystals begin to form in a supercooled liquid. Ice crystals typically form around impurities or on solid surfaces. Without nucleation sites, the water can remain in a supercooled state, where it is still a liquid even below its freezing point. Supercooling is the reason why water in very pure and clean containers can be cooled below its freezing point without solidifying.
Activation Energy: The formation of ice requires an input of energy to overcome the energy barrier associated with breaking intermolecular bonds in the liquid water and forming the solid crystal structure. This energy is referred to as the activation energy. As the temperature is lowered, it becomes more difficult for water molecules to gain enough energy to overcome this barrier and initiate the formation of ice crystals.
Kinetics: Even once nucleation occurs, the growth of ice crystals takes time due to kinetic factors. The movement of water molecules becomes slower as the temperature decreases, reducing the rate of crystal growth. The rate at which ice forms depends on factors such as temperature, pressure, and the presence of impurities.
So, while it is theoretically possible to eventually freeze water by continuously lowering the temperature, the process is not instantaneous. It requires time for heat transfer, nucleation, and crystal growth to occur. These factors contribute to the observed behavior of substances during phase changes and the overall consistency of natural laws and principles governing physical processes.