Ausfrieren

Ausfrieren is a German verb meaning to freeze or to become frozen. In everyday use it describes the transition of a substance from a liquid to a solid when the temperature falls, or the effect of cold on living tissue. The term is used in several scientific and practical contexts.

In meteorology and environmental science, Ausfrieren refers to the formation of ice or frost on surfaces as air temperatures drop. It encompasses phenomena such as frost on plants and in the atmosphere, as well as soil freezing. When water in the soil freezes, the resulting expansion can cause frost heave and ground movement.

In medicine and physiology, Ausfrieren denotes frostbite, the injury caused by freezing of skin and underlying tissues. Early frostbite is called frostnip. Symptoms include numbness, tingling, and pale or waxy skin; severe cases can lead to tissue damage. Prevention relies on proper insulation and warming of affected areas, and treatment depends on injury severity and medical guidance.

In chemistry and process engineering, Ausfrieren describes a freeze-out process: cooling a mixture so that a component crystallizes and can be separated as a solid. This technique is used in cryogenics, gas purification, and certain food-processing applications.

Overall, Ausfrieren covers natural freezing phenomena as well as engineered methods that rely on lowering temperature to separate, preserve, or protect materials and tissues.