In many countries there is still talk of degrees Celsius to refer to temperature or wind chill. However, this unit of measurement has disappeared for many years. Therefore, it is true that degrees centigrade do not exist. And then we explain why they continue to be used or even wrongly equated to degrees Celsius. Keep reading!
Degrees centigrade or Celsius: an old but still valid confusion
Since 1948, degrees Celsius have been replaced by Celsius in the International System of Units. Consequently, the Celsius degree, together with the Kelvin, have become the unit of measurement for the current temperature in Spain and much of Latin America.
Thus, at present it would be a mistake to express ambient and body temperatures in degrees Celsius. However, references to this unit of measurement remain common, as well as the confusion between degrees Celsius and centigrade.
This confusion, indeed, has a historical origin. It happens that, at the end of the 19th century, the International Committee of Weights and Measures decided to adopt the centigrade scale of the constant volume hydrogen thermometer as a thermometric scale for the International Bureau of Weights and Measures (BIPM).
What do they mean and why do degrees Celsius no longer exist?
This centigrade scale had about fixed points representing the melting temperature of ice (0 ° C) and boiling point of distilled water (100 ° C). And one degree centigrade would correspond to one hundredth of the difference between these points at normal pressure.
Following the Committee’s decision, this unit of measurement (degrees centigrade) became the “official” to express temperature. But, in 1948, the need for replace the melting point of ice with the triple point of water, which could be defined and reproduced more precisely.
It should be explained that the triple point is one in which the three states of a substance (solid, liquid and gaseous) coexist, and is determined in relation to a pressure and a temperature. Furthermore, at that same time the proposal made since 1854 by Lord Kelvin of adopt a single fixed point to define the thermodynamic temperature.
The “birth” of degree Celsius
Many discussions later, both ideas would be approved by the Committee. Then the triple point of water would “gain” an assigned value of 0.01 ° C (corresponding to 273.16 K) and would become the mainstay of the temperature scale.
And at the end of the year 1948, the General Conference on Weights and Measures replaces the nomenclature of “degrees Celsius” with “degrees Celsius”. A tribute to Anders Celsius, a Swedish astronomer, physicist and thermometrist who had idealized the centigrade scale.