Supercooling



Supercooling is the process of chilling a solid.

Description


A liquid below its freezing point will amorphous—that is, non-crystalline—solid.

Water has a freezing point of 273.15 K (0 °C or 32 °F) but can be supercooled at standard pressure down to its crystal homogeneous nucleation at almost 231 K (−42 °C).[1] If cooled at a rate on the order of 106 K/s, the crystal nucleation can be avoided and water becomes a glass. Its glass transition temperature is much colder and harder to determine, but studies estimate it at about 165 K (−108 °C).[2] Glassy water can be heated up to approximately 150 K (−123 °C).[1] In the range of temperatures between 231 K (−42 °C) and 150 K (−123 °C) experiments find only crystal ice.

Droplets of supercooled water often exist in stratiform and cumulus clouds. They form into deicing system.) Freezing rain is also caused by supercooled droplets.

An equivalent to supercooling for the process of melting solids is much more difficult, and a solid will almost always melt at the same boiling point without it becoming gaseous.[citation needed]

See also

References

  • Debenedetti, P. G.; Stanley, H. E. (2003). "Supercooled and Glassy Water" (PDF). Physics Today 56 (6): 40–46.
  • Giovambattista, N.; Angell, C. A.; Sciortino, F.; Stanley, H. E. (July 2004). "Glass-Transition Temperature of Water: A Simulation Study" (PDF). Physical Review Letters 93 (4).
  • Rogerson, M. A.; Cardoso, S. S. S. (April 2004). "Solidification in heat packs: III. Metallic trigger". AIChE Journal 49 (2): 522–529.
  1. ^ a b Debenedetti, p. 42.
  2. ^ Giovambattista, p. 047801-1.
 
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