Ylijäähtyneen

Ylijäähtyneen, meaning "supercooled" in English, refers to a state where a liquid is cooled below its freezing point without solidifying. This phenomenon occurs when the liquid does not contain any impurities or surfaces that can act as nucleation sites for crystal formation. In the absence of these nucleation sites, the molecules in the liquid remain in a disordered state, even at temperatures below their normal freezing point.

When a supercooled liquid is disturbed, such as by shaking or introducing a nucleation site, it can rapidly crystallize. This rapid crystallization releases latent heat, causing a noticeable temperature increase. A common demonstration involves supercooled water. If a bottle of water is carefully cooled below 0 degrees Celsius and then poured onto an ice cube, the water will instantly freeze upon contact, creating intricate ice structures.

Supercooling is a delicate process and requires careful control of environmental conditions. Even slight vibrations or the presence of dust particles can trigger crystallization. This state is not stable and will eventually transition to the solid phase. While seemingly a scientific curiosity, the principles of supercooling have applications in fields such as weather forecasting, where it plays a role in cloud formation and precipitation, and in cryopreservation.