Suprajäähtymistila

Suprajäähtymistila, also known as supercooling, refers to the process of cooling a liquid or a gas below its freezing point without it becoming solid. This state is metastable, meaning it is not the most stable form of the substance under normal conditions. In a suprajäähtymistila, the molecules of the liquid have not yet organized into the crystalline structure of a solid, even though the temperature is below the normal freezing point.

The phenomenon of suprajäähtymistila is possible because the formation of a solid crystal requires nucleation sites. These sites can be impurities in the liquid or imperfections on the container surface. If a liquid is very pure and its container is smooth, it can be cooled below its freezing point without any nucleation occurring. The liquid remains in a liquid state, but it is highly susceptible to sudden solidification.

A disturbance, such as shaking the container, introducing a seed crystal, or even a sudden temperature fluctuation, can trigger the nucleation process. Once nucleation begins, the solidification process often happens very rapidly, releasing the latent heat of fusion and causing the temperature to rise to the normal freezing point. Suprajäähtymistila is observed in various substances, including water, which can be supercooled to around -40 degrees Celsius under ideal laboratory conditions. This principle is utilized in some industrial processes and scientific experiments.