AskDefine | Define calorie

Dictionary Definition

calorie

Noun

1 unit of heat defined as the quantity of heat required to raise the temperature of 1 gram of water by 1 degree centigrade at atmospheric pressure [syn: gram calorie, small calorie]
2 a unit of heat equal to the amount of heat required to raise the temperature of one kilogram of water by one degree at one atmosphere pressure; used by nutritionists to characterize the energy-producing potential in food [syn: kilogram calorie, kilocalorie, large calorie, nutritionist's calorie]

User Contributed Dictionary

English

Noun

  1. a non-SI unit of energy, widely used in chemistry and physics, being the amount of heat needed to raise the temperature of 1 gram of water by 1°C
  2. a unit of energy equal to 1,000 calories; used in nutrition; a kilocalorie

Translations

Italian

Noun

calorie
  1. Plural of caloria

Extensive Definition

This article is about the unit of energy. For its use in nutrition and food labelling regulations, see the article on food energy.
The calorie is a pre-SI unit of energy, in particular heat. In most fields, its use is archaic, and the SI unit of energy, the joule, has become accepted. However, it remains in common use as a unit of food energy. It was first defined by Professor Nicolas Clément in 1824 as a kilogram-calorie, and this definition entered French and English dictionaries between 1841 and 1867. Etymology: French calorie, from Latin calor (heat).
The unit calorie has historically been used in two major alternate definitions that differ by a factor of 1000:
  • The small calorie, gram calorie, or calorie (symbol: cal) is the amount of heat (energy) required to raise the temperature of one gram of water by 1 °C.
  • The large calorie, kilogram calorie, kilocalorie (symbol: kcal), or Calorie (capital C) is the amount of heat (energy) needed to increase the temperature of one kg of water by 1 °C, exactly 1000 small calories, or about 4.184 kJ.
The second form is the one commonly used to express food energy. Its most common name is calorie; kilocalorie is sometimes used, more often in the symbol "kcal" than in the spelled out word.
Apart from these two major alternate definitions, there exist also minor variants of the definition of this unit, which differ in the exact experimental conditions used, most notably the start temperature of the water (see section below).
The factors used to convert measurements in calories to their equivalents in joules are numerically equivalent to expressions of the specific heat capacity of water in SI units. See "Versions" below for an explanation of the units.
1 calIT = 4.1868 J (1 J = 0.23885 calIT) (International Steam Table calorie, 1956)
1 calth = 4.184 J (1 J = 0.23901 calth) (Thermochemical calorie)
1 cal15 = 4.18580 J (1 J = 0.23890 cal15) (15°C calorie)

Versions

The energy needed to increase the temperature of a gram of water by 1 degree Celsius depends on the starting temperature and is difficult to measure precisely. Accordingly, there have been several definitions of the calorie:
The two perhaps most popular definitions used in older literature are the "15 °C calorie" and the "thermochemical calorie". Since the many different definitions are a source of confusion and error, all calories are now deprecated in favour of the SI unit for heat and energy: the joule (J).

References

calorie in Arabic: سعرة حرارية
calorie in Bosnian: Kalorija
calorie in Bulgarian: Калория
calorie in Catalan: Caloria
calorie in Czech: Kalorie
calorie in Danish: Kalorie
calorie in German: Kalorie
calorie in Estonian: Kalor
calorie in Modern Greek (1453-): Θερμίδα
calorie in Spanish: Caloría
calorie in Esperanto: Kalorio
calorie in Persian: کالری
calorie in French: Calorie (unité)
calorie in Galician: Caloría
calorie in Korean: 칼로리
calorie in Croatian: Kalorija
calorie in Indonesian: Kalori
calorie in Italian: Caloria
calorie in Hebrew: קלוריה
calorie in Luxembourgish: Kalorie
calorie in Lithuanian: Kalorija
calorie in Malay (macrolanguage): Kalori
calorie in Dutch: Calorie
calorie in Japanese: カロリー
calorie in Norwegian: Kalori
calorie in Polish: Kaloria
calorie in Portuguese: Caloria
calorie in Romanian: Calorie
calorie in Russian: Калория
calorie in Slovenian: Kalorija
calorie in Serbian: Калорија
calorie in Sundanese: Kalori
calorie in Finnish: Kalori
calorie in Swedish: Kalori
calorie in Thai: แคลอรี
calorie in Vietnamese: Ca-lo
calorie in Turkish: Kalori
calorie in Ukrainian: Калорія
calorie in Yiddish: קאלערי
calorie in Chinese: 卡路里

Synonyms, Antonyms and Related Words

BTU, British thermal unit, atomerg, dinamode, dyne, energid, erg, foot-pound, great calorie, horsepower-hour, horsepower-year, joule, kilocalorie, kilogram-meter, kilowatt-hour, photon, quantum, rational calorie, therm, thermal unit
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