Cold

Cold (having less heat) refers to the condition or subjective perception of having low temperature.

The coldest theoretically possible temperature is absolute zero, also called absolute temperature, which is 0 K on the Kelvin scale, a thermodynamic temperature scale, and −273.15 °C on the Celsius scale. Absolute zero is also 0 R on the Rankine scale, another thermodynamic temperature scale, and −459.67 degrees on the Fahrenheit scale.

Since temperature relates to the thermal energy held by an object or a sample of matter, which is the kinetic energy of the random motion of the particle constituents of matter, an object will contain less thermal energy when it is cold than when it is hot. If it were possible to cool a system to absolute zero, all motion of the particles comprising matter would cease and they would be at complete rest in this classical sense. The object would be described as having zero thermal energy. Microscopically in the description of quantum mechanics, however, matter still has zero-point energy even at absolute zero, because of the uncertainty principle.

Contents

Mammalian perception

Mammals have an endothermic ("warm-blooded") physiology . Therefore they have a perception of thermal comfort that is centered around their body temperature. Their thermal comfort is dependent upon their metabolism and environmental surroundings, and is affected by heat conduction, convection, radiation, and evaporative heat loss. Thermal comfort is maintained when the heat generated by their metabolism is allowed to dissipate, thus maintaining thermal equilibrium with the surroundings. When this equilibrium is not maintained due to excessive heat loss, then they will perceive the feeling of being too cold, and in varying degrees of discomfort depending upon how far this equilibrium is skewed.[citation needed]

Cooling

Cooling refers to the process of becoming cold, or lowering in temperature. This could be accomplished by removing heat from a system, or exposing the system to an environment with a lower temperature.

Fluids used to cool objects are commonly called coolants.

Air cooling is the process of cooling an object by exposing it to air. This will only work if the air is at a lower temperature than the object, and the process can be enhanced by increasing the surface area or decreasing the mass of the object.

Another common method of cooling is exposing an object to ice, dry ice, or liquid nitrogen. This works by convection; the heat is transferred from the relatively warm object to the relatively cold coolant.

Laser cooling and Magnetic evaporative cooling are techniques used to reach very low temperatures.

Notable cold locations and objects

See also


References


Wikimedia Foundation. 2010.

Synonyms:

Look at other dictionaries:

  • Cold-fX — is a product derived from the roots of North American ginseng (Panax quinquefolius) that is manufactured by Afexa Life Sciences Inc. (formerly called CV Technologies Inc.)[1], headquartered in Edmonton, Alberta, Canada. It is marketed as a daily… …   Wikipedia

  • Cold — Datos generales Origen Jacksonville, Florida, Estados Unidos …   Wikipedia Español

  • Cold — (k[=o]ld), a. [Compar. {Colder} ( [ e]r); superl. {Coldest}.] [OE. cold, cald, AS. cald, ceald; akin to OS. kald, D. koud, G. kalt, Icel. kaldr, Dan. kold, Sw. kall, Goth. kalds, L. gelu frost, gelare to freeze. Orig. p. p. of AS. calan to be… …   The Collaborative International Dictionary of English

  • cold — [kōld] adj. [ME < OE (Anglian) cald < IE base * gel , cold > COOL, Ger kalt, L gelidus] 1. of a temperature significantly or noticeably lower than average, normal, expected, or comfortable; very chilly; frigid [a cold wind] 2. a) without …   English World dictionary

  • cold — cold, cool, chilly, frigid, freezing, frosty, gelid, icy, glacial, arctic mean having a temperature below that which is normal or comfortable. Cold is the general term, often implying nothing more than a lack of warmth {a cold day} {a cold hand}… …   New Dictionary of Synonyms

  • cold — ► ADJECTIVE 1) of or at a low or relatively low temperature. 2) not feeling or showing emotion or affection. 3) not affected by emotion; objective: cold statistics. 4) (of a colour) containing pale blue or grey and giving no impression of warmth …   English terms dictionary

  • Cold — Cold, n. 1. The relative absence of heat or warmth. [1913 Webster] 2. The sensation produced by the escape of heat; chilliness or chillness. [1913 Webster] When she saw her lord prepared to part, A deadly cold ran shivering to her heart. Dryden.… …   The Collaborative International Dictionary of English

  • cold — cold; cold·ish; cold·ness; cold·slaw; cold·heart·ed·ly; cold·heart·ed·ness; …   English syllables

  • Cold — (англ.  холодный)  многозначный термин, который может означать: COLD  американская группа, играющая пост гранж/альтернативный металл, из Джексонвилля, Флорида. Cold  сингл группы Static X. Cold  студийный альбом блэк… …   Википедия

  • COLD — bezeichnet eine US amerikanische Alternative Metal/Post Grunge Band, siehe Cold (Band). COLD bezeichnet ein Verfahren zur Daten Archivierung in Computer Systemen, siehe Computer Output on Laserdisk die chronic obstructive lung disease, siehe… …   Deutsch Wikipedia

  • Cold — bezeichnet eine US amerikanische Alternative Metal/Post Grunge Band, siehe Cold (Band). ein Album von Flotsam and Jetsam, siehe The Cold. COLD bezeichnet ein Verfahren zur Daten Archivierung in Computer Systemen, siehe Computer Output on… …   Deutsch Wikipedia


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.