1 the process whereby heat changes something from a solid to a liquid; "the power failure caused a refrigerator melt that was a disaster"; "the thawing of a frozen turkey takes several hours" [syn: thaw, melt, melting]
2 warm weather following a freeze; snow and ice melt; "they welcomed the spring thaw" [syn: thaw, warming]
- present participle of thaw
Melting is a process that results in the phase change of a substance from a solid to a liquid. The internal energy of a solid substance is increased (typically by the application of heat) to a specific temperature (called the melting point) at which it changes to the liquid phase. An object that has melted completely is molten.
The melting point of a substance is a characteristic property. The melting point may not be equal to the freezing point. This is evident in the phenomenon known as supercooling. In the case of water, ice crystals typically require a seed on which to begin formation. Water on a very clean glass surface will often supercool several degrees below the melting point without freezing. Fine emulsions of pure water have been cooled to -38 degrees celsius without the nucleation of ice taking place. For this reason, melting point is a characteristic property of a substance while freezing point is not.
Molecular vibrationsWhen the internal energy of a gas is increased by the application of an external energy source, the molecular vibrations of the substance increases. As these vibrations increase, the substance becomes more and more ordered. Fusion is also another term used for this.
Constant temperatureSubstances melt at a constant temperature, the melting point. Further increases in temperature (even with continued application of energy) do not occur until the substance is molten.
The thermodynamics of meltingFrom a thermodynamics point of view, at the melting point the change in Gibbs free energy (\Delta G) of the Material is zero, because the enthalpy (H) and the entropy (S) of the material are increasing (\Delta H, \Delta S > 0). Melting phenomenon happens when the Gibbs free energy of the liquid becomes lower than the solid for that material. At various pressures this happens at a specific temperature. It can also be shown that:
\Delta S = \frac
The "T","\Delta S", and "\Delta H" in the above are respectively the temperature at the melting point, change of entropy of melting, and the change of enthalpy of melting.
Other meaningsIn genetics, melting DNA means to separate the double-stranded DNA into two single strands by heating or the use of chemicals.
- See also : Polymerase chain reaction
thawing in Bulgarian: Топене
thawing in Catalan: Fusió (canvi d'estat)
thawing in Czech: Tání
thawing in Danish: Smeltning
thawing in German: Schmelzen
thawing in Estonian: Sulamine
thawing in Modern Greek (1453-): Τήξη
thawing in Spanish: Fusión (cambio de estado)
thawing in Basque: Urtze
thawing in Persian: ذوب
thawing in French: Fusion (physique)
thawing in Italian: Fusione (fisica)
thawing in Hebrew: התכה
thawing in Latvian: Kušana
thawing in Lithuanian: Lydymasis
thawing in Dutch: Smelten (faseovergang)
thawing in Japanese: 融解
thawing in Low German: Smölten
thawing in Polish: Topnienie
thawing in Portuguese: Fusão
thawing in Russian: Плавление
thawing in Simple English: Melting
thawing in Slovak: Topenie
thawing in Slovenian: Taljenje
thawing in Finnish: Sulaminen
thawing in Swedish: Smältning
thawing in Tamil: உருகுதல்
thawing in Turkish: Erime
thawing in Ukrainian: Плавлення
thawing in Chinese: 融化
colliquation, colliquative, decoagulation, deliquescence, deliquium, dissolution, dissolutional, dissolutive, dissolving, fluidification, fluidization, fusibility, fusing, fusion, leaching, liquation, liquefaction, liquefactive, liquefying, liquescence, liquescency, lixiviation, melting, percolation, running, solubilization, solution, thaw, thermoplasticity, unclotting