freezes

Freezes refers to the transition from liquid to solid when a substance’s temperature falls to or below its freezing point. The term is used across physics, chemistry, meteorology, and everyday language to describe both the phase change itself and episodes of freezing temperatures in the environment.

In pure substances, freezing begins with nucleation—the formation of small solid clusters—that grow as thermal energy is removed. The temperature at which this occurs is the freezing point; for water at one atmosphere of pressure, it is 0°C. In real systems, impurities, pressure, and confinement can alter freezing behavior, leading to phenomena such as supercooling or mixed-phase states. The process releases latent heat of fusion.

Freezing has broad practical and environmental consequences. Frost forms on surfaces when water vapor deposits as ice. Ice on roads and crops can create hazards and cause damage. Freeze–thaw cycles, involving repeated freezing and thawing, can deteriorate materials and structures over time.

Applications of freezing include food preservation, where low temperatures slow microbial growth and chemical reactions; freeze-drying, which removes water by sublimation under low temperature and pressure; and cryopreservation, where cells or tissues are preserved by carefully controlled cooling. Industrial and laboratory processes also rely on freezing for temperature control and material handling.

Biology and materials science examine how organisms and substances cope with freezing. Some organisms exhibit freeze tolerance or employ antifreeze proteins to control ice formation, while researchers study ice nucleation and the effects of ice on cellular integrity. Understanding freezes informs meteorology, food technology, medicine, and engineering.