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Degree Celsius

Degree Celsius

The degree Celsius (in symbol in ° C), is the unit of a temperature measurement scale, named after the Swedish astronomer Anders Celsius (1701 - 1744), who proposed it for the first time in 1742.

The Celsius scale fixes the melting point of ice in a mixture of water saturated with air at 0 ° C and boiling point at 99.974 ° C under standard pressure conditions (1 bar, a little less than one atmosphere, pressure in the that the water boils at 100 degrees Celsius).

Originally conceived by the scale Celsius had the boiling point of water at 0 ° C, and the freezing point of 100 ° C. After his death, however, the scale was reversed in 1745 by Linnaeus, transforming it into what is now commonly used.

The current official definition of the Celsius scale places 0.01 ° C as the triple point of water and one degree as 1 / 273.16 of the temperature difference between the triple point of water and the absolute zero. This Celsius grade definition ensures that the temperature difference of one degree Celsius represents the same temperature difference of a kelvin.

Conversion of degree Celsius to other units of temperature

Formulas to convert the degree Celsius to other units of temperature.

  • Conversion from Celsius degree to Fahrenheit degree ° F = (9/5 × C) + 32
  • Conversion of Fahrenheit degree to Celsius degree à ° C = (5/9) × (° F - 32)
  • Conversion of degree Celsius to kelvin à K = ° C + 273.15
  • Conversion of Kelvin to Celsius degree à ° C = K - 273.15

Anders Celsius originally proposed that the freezing point was 100 ° C and the boiling point 0 ° C. The ladder was reversed in 1745 at the suggestion of Linnaeus, or perhaps by Daniel Ekström, the producer of most thermometers used by Celsius.

The thermometric scales of Celsius and Fahrenheit cross at the same value of -40 degrees, that is, the value of -40 ° C corresponds to -40 ° F.

One method to convert Celsius to Fahrenheit is to multiply by 1.8 and add 32.

° F = ° C × 1.8 + 32

Conversely, to convert Fahrenheit to degrees Celsius, subtract 32 and divide by 1.8.

° C = (° F - 32) / 1.8

The Celsius scale is used in most of the world on a daily basis, although in the mass media it is still called Celsius until the nineties, especially in the weather forecast. In the United States (as well as in the unincorporated territories and the freely associated states of the Pacific), the Fahrenheit scale is used in Belize, Liberia and some Caribbean islands, but these countries also use the Celsius scale or the Kelvin scale in the scientific or technological.

Other temperature scales are: Newton (circa 1700), Rømer (1701), Fahrenheit (1724), Réaumur (1731), Delisle or Lisle (1738), Rankine (1859), Kelvin (1862) and Leyden (circa 1894) . Note that " Kelvin" is lowercase because it is an SI unit, even if derived from the noble title of scientist William Thomson.

Celsius degree

Since there are a hundred divisions between these two reference points, the original term for this system was centigrade or centesimal grade. In 1948, the ninth Conférence générale des poids et mesures (CR 64) officially changed the name to Celsius to eliminate a series of ambiguities:

  • the prefix centi is used by the SI system for submultiples;
  • a more correct name, at least since Linnaeus was invested, would have been "hectograted";
  • also the hectogram is ambiguous and in enology it indicates the alcohol content per hectolitre of wine;
  • the term "Celsius degree" was also used to indicate the centesimal grade used to measure angles;
  • also the Kelvin is a degree Celsius, as far as the obtained thing, like Celsius, dividing in equal parts the interval between two fundamental fixed points.

The decision of the Conférence générale des poids et mesures was aimed at eliminating ambiguities and unambiguously associating the creation of the scale with Celsius (despite the important contribution of Linnaeus); in addition, the scale was uniform to those of Kelvin, Fahrenheit, Réaumur and Rankine, all with the name of its inventor. Despite this, in Italy it often refers to degrees centigrade as "degrees centigrade".

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Last review: October 25, 2018