Celsius Scale

Celsius scale is also called the centigrade scale. Celsius scale definition can be given as the temperature scale based on 100° for the boiling point, and 0° for the freezing point of water. This scale was first introduced and is named after by the Swedish Physicist, Engineer, and Astronomer,  Anders Celsius. 

Initially, the celsius scale was used at 0° to denote the boiling point of water and 1000° to denote the freezing point of water. Later, these values were inverted to 0° for the freezing point and 100° for the boiling point of water. This type of the celsius scale gained widespread use.

Notes on Celsius Scale

Celsius temperatures follow either a system of a relative interval or scale, rather than an absolute system of ratio or scale. The Ratio scale type includes the ones used for the calculation of weight or distance. For suppose, when the mass is doubled (let us say from 10 kg to 20 kg), usually, it is accompanied by an increase in volume, which values for twice the amount of matter. The increased level in this amount of matter from 10 kg to 20 kg is similar to the increase in the amount of matter running from 50 kg to 60 kg. 

However, it is also important to make a note that the Celsius scale does not work with heat energy in this mode. The disparity between 10°C and 20°C to that of between 20°C and 30°C is only 10° because a temperature of 20°C does not have two times of heat energy that is exerted by a temperature of 10°C.

The Modern Celsius Scale

Modern Celsius scale is also referred to be based on the triple point of Vienna Standard Mean Ocean Water, and on the concept of absolute zero as well. This implies that neither the boiling point nor the melting point of water describes the modern celsius scale. 

It is to make a note that the differences arise between the formal and common definitions of the celsius scale can be considered to be insignificant when it comes to practical settings. It should also remember that there exists a difference of only 16.1 millikelvins between the modern scales calculation of the boiling point of water to that of the original scales calculation.

Centigrade versus Celsius

Since the 19th century, the worldwide thermometry and scientific communities have used the term "centigrade scale," and often temperatures were reported simply as "degrees" or, as "degrees centigrade," when greater specificity was desired, with the symbol °C.

However, the term centigrade was also used in the French and Spanish language as an angular measurement unit (which is 1/100 of a right angle), with a similar connotation in other languages. The term gradient or centesimal degree ("gon" or "grad": 1ᵍ = 0.9°, 100ᵍ = 90°) was used when an unambiguous language was needed by the international standards bodies like the BIPM. Properly, it would more now be called "hectograde."

To get rid of the confusion between the unit of angular measurement and unit of temperature, the 9th meeting of the General Conference on Weights & Measures and the Comite International des Poids et Mesures adopted the "degree Celsius" formally in 1948 for the degree of temperature, and keeping the recognized degree symbol (°), rather than adopting the centesimal or gradian degree symbol (gon or ᵍ).

Usually, for scientific use, "Celsius" is the term used, but in English-speaking countries, "centigrade" remains a common use, especially in informal contexts. It was not even until February 1985, where the weather forecasts issued by the BBC had switched the term from "centigrade" to "Celsius."

Differences between the Celsius Scale vs. Fahrenheit Scale

Let us discuss the key differences between the Celsius scale and the Fahrenheit Scale tabulated below: