Degree symbol with Celsius

For many years the Celsius scale was called the centigrade scale. Recently, the decision was made to name all temperature scales after their creators, although you may sometimes still see centigrade in use. It is also conventional to use the degree (°) symbol with Celsius and Fahrenheit temperatures, but not with Kelvin temperatures, although you will probably see used by some authors. 

The SI unit of Celsius temperature is the degree Celsius, °C, which is equal to the kelvin, K. °C should be treated as a single symbol, with no space between the ° sign and the letter C. (The symbol °K, and the symbol °, should no longer be used.)... 

Spacing, hyphens, and italics. When a unit symbol is given after a number, a space is always left between the number and the symbol with the exception of cases where the symbol appears in the superscript position, such as degree, minute, and second of plane angles. The symbol for degree Celsius may be written either with or without a space before the degree symbol. For example,... 

The SI unit is the kelvin, K. The degree Celsius scale has units of the same magnitude, °C, but starts at 273.15 K, the melting point of ice at STP. Temperature is similar to time in that the Celsius scale is in widespread use, but note that conversions to K may be required for calculations. Note also that you must not use the degree sign (°) with K and that this symbol must be in upper case to avoid confusion with k for kilo however, you should retain the degree sign with °C to avoid confusion with the coulomb, C. 

The divisions of the Fahrenheit and Celsius scales are called degrees, but the divisions of the Kelvin scale are called kelvins (K). The kelvin is the SI rmit of temperature. Note that the degree symbol is not used with temperatures expressed in kelvins. For example, absolute zero is written as 0 K. On the Celsius scale, the temperature reading for absolute zero is —273.15°C, usually rounded to —273°C. A Celsius degree and a kelvin are the same size, so by shifting the Celsius scale up 273°, it will coincide with the Kelvin scale. 

You probably use the Fahrenheit scale to measure temperatures, but most scientists and chemists use either the Celsius CC) or Kelvin (TQ temperature scale. (There s no degree symbol associated with K.) Figure 2-4 compares the three temperature scales using the freezing point and boiling point of water as reference points. 

The degree symbol is used with the Celsius and Fahrenheit scales, but not with the Kelvin scale. 

Name, Symbol kelvin, K-(temperature) Definition The kelvin is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water. The kelvin is a unit of thermodynamic temperature (T). The word (or symbol) degree is not used with kelvin. The Celsius (formerly centigrade) temperature is also used. Celsius temperature (symbol f) is defined by the equation t = T — T0, where T0 equals 273.15 K. A degree Celsius (°C) is thus equal to one kelvin. 

William Thomson (1824-1907), known as Lord Kelvin, first suggested using gas thermometers for measuring temperature. The absolute temperature scale is named after him. The Kelvin scale has units called kelvins, symbolized K, which are the same size as Celsius degrees. The word degree and the symbol for degrees (°) are not used with the Kelvin scale. The Kelvin (absolute) scale must be used in all gas law problems involving temperature. 

For the temperature scale, SI rules allow the use of degrees Celsius, symbol °C, but not for temperature intervals nor can °C it be used with a prefix. For example cool the liquid to —15°C at a rate of lOmK s 1. 

Unknown to most physical scientists, there exists another important meaning for the °C symbol—degrees Crerar. The Crerar Scale has a single, fixed equilibrium state—an aqueous solution 3 molal in NaCl, 0.001 mo-lal in H2S, at a pH of 4 and saturated with sphalerite (ZnS) at atmospheric pressure and a molality of zinc of exactly 10 . This state has been found to have a temperature of 100°C on the Celsius scale, and is defined as 1234°C on the absolute Crerar Scale. Find the temperature of freezing water on the Crerar scale. Is the Crerar Scale a Thermodynamic one ... 

Another temperature scale, used in Canada and Europe and in the physical and life sciences in most countries, is the Celsius scale. In keeping with the metric system, which is based on powers of 10, the freezing and boiling points of water on the Celsius scale are assigned as 0 °C and 100. °C, respectively. On both the Fahrenheit and the Celsius scales, the unit of temperature is called a degree, and the symbol for it is followed by the capital letter representing the scale on which the units are measured °C or °F. 

The symbol for the Celsius and Fahrenheit degrees is and it is placed as a superscript after the number and before the symbol for the scale. Thus, 10.0°C means 10.0 degrees Celsius. The degree sign is not used with Kelvin temperatures ... 

It is common practice to express a thermodynamic temperature, symbol T, in terms of its difference from the reference temperature = 273.15 K. The numerical value of a Celsius temperature t expressed in degrees Celsius is given by t/ C = r/K-273.15. The unifC maybe used in combination with SI prefixes, e.g., millidegree Celsius, m C. Note that there should never be a space between the sign and the letter C, and that the symbol for kelvin is K, not T<. 

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