Browse Definitions:
Definition

calorie (cal)

The calorie (symbolized cal) is a unit of heat occasionally used in the centimeter-gram-second ( cgs ) system of physical units. Heat is a form of kinetic energy transfer from one medium or object to another.

When 1 cal of heat energy is transferred to one gram (1 g) of pure liquid water, the temperature of that sample of water is raised by one degree Celsius (1º C) or one degree Kelvin (1º K), provided the water temperature is above the freezing point and below the boiling point. When the temperature of 1 g of pure liquid water falls by 1º C or 1º K, that water gives up 1 cal of heat energy. (The Celsius degree and the Kelvin degree represent a temperature increase or decrease of the same amount, although the scales are offset by 273.15.) One gram of pure liquid water has a volume of one centimeter cubed (1 cm3) or one milliliter (1 ml).

In nutrition, a unit called the kilocalorie, also known as the diet calorie, is frequently mentioned. This unit is equivalent to 1000 cal, and is the amount of heat energy required to raise or lower one kilogram (1 kg) of pure liquid water by 1º C or 1º K. When the label on a package of food says that a serving contains 200 calories, it means that the sample would yield 200 kcal (not 200 cal) of heat energy if subjected to complete combustion. Kilocalories are used (and misused) to express the amount of food consumed in a serving, a meal, or a day. It has been said that a surplus of 7700 kcal of food intake will result in a mass gain of 1 kg, or that a surplus of 3500 kcal of food intake will produce a weight gain of one pound (1 lb), which represents 0.454 kg in the gravitational field of the earth at the surface. Some nutritionists and physicians, however, point out that this is a simplistic view, and can lead to abusive dieting and the neglect of physical activity as a factor in the maintenance of ideal weight and overall health.

In physics, the standard unit of energy or work is the joule (symbolized j). One calorie is the equivalent of approximately 4.1868 j. Conversely, 1 j is the equivalent of approximately 0.23885 cal. Other, less common, units of energy include the British thermal unit ( Btu ) and the erg . The Btu is equivalent to approximately 1055 j, and the erg is equivalent to exactly 0.0000001 (10-7) j. The Btu is sometimes used in reference to residential and commercial heating and air conditioning systems. The erg is occasionally specified when it is necessary to express extremely small quantities of energy.

Also see energy , heat , International System of Units ( SI ), and Table of Physical Units .

This was last updated in March 2011

Join the conversation

1 comment

Send me notifications when other members comment.

By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy

Please create a username to comment.

I need to increase the calories in falling Flim evaporators at constant temperature
to reduce the cooking time
Cancel

-ADS BY GOOGLE

File Extensions and File Formats

SearchCompliance

  • internal audit (IA)

    An internal audit (IA) is an organizational initiative to monitor and analyze its own business operations in order to determine ...

  • pure risk (absolute risk)

    Pure risk, also called absolute risk, is a category of threat that is beyond human control and has only one possible outcome if ...

  • risk assessment

    Risk assessment is the identification of hazards that could negatively impact an organization's ability to conduct business.

SearchSecurity

  • phishing

    Phishing is a form of fraud in which an attacker masquerades as a reputable entity or person in email or other communication ...

  • vulnerability disclosure

    Vulnerability disclosure is the practice of publishing information about a computer security problem, and a type of policy that ...

  • incident response

    Incident response is an organized approach to addressing and managing the aftermath of a security breach or cyberattack, also ...

SearchHealthIT

SearchDisasterRecovery

  • business continuity and disaster recovery (BCDR)

    Business continuity and disaster recovery (BCDR) are closely related practices that describe an organization's preparation for ...

  • business continuity plan (BCP)

    A business continuity plan (BCP) is a document that consists of the critical information an organization needs to continue ...

  • call tree

    A call tree -- sometimes referred to as a phone tree -- is a telecommunications chain for notifying specific individuals of an ...

SearchStorage

  • flash memory

    Flash memory, also known as flash storage, is a type of nonvolatile memory that erases data in units called blocks.

  • NAND flash memory

    NAND flash memory is a type of nonvolatile storage technology that does not require power to retain data.

  • NOR flash memory

    NOR flash memory is one of two types of nonvolatile storage technologies.

SearchSolidStateStorage

  • hybrid hard disk drive (HDD)

    A hybrid hard disk drive is an electromechanical spinning hard disk that contains some amount of NAND Flash memory.

Close