Unterkühltes

Unterkühltes refers to a state where a liquid is cooled below its normal freezing point without becoming solid. This is a metastable state, meaning it is not the most stable phase. For water, this phenomenon can occur when it is pure and free from impurities that can act as nucleation sites. If disturbed, such as by a slight jolt or the introduction of a solid particle, the supercooled liquid will rapidly freeze. This rapid freezing is an exothermic process, releasing heat as the liquid transitions to a solid state.

The concept of unterkühltes is important in various scientific fields. In meteorology, it plays a role in the formation of hail and ice crystals in clouds. Supercooled water droplets can exist in the atmosphere even at temperatures below 0 degrees Celsius. When these droplets encounter ice particles or other supercooled droplets, they can freeze almost instantaneously, contributing to the growth of precipitation. In cryogenics and food preservation, understanding and controlling supercooling can be crucial for preserving biological samples and extending the shelf life of perishable goods. Special techniques are employed to achieve controlled freezing or to prevent unwanted supercooling.