B Symbol for temperature on the Fahrenheit scale

[DrDu]

IUPAC recommends T as the symbol for absolute temperature and t or theta for temperature on the Celsius scale. While Fahrenheit scale is not recommended, it is nevertheless widespread and the question arises if there is a widely accepted symbol for the respective quantity.

 

[kuruman]

IUPAC recommends T as the symbol for absolute temperature and t or theta for temperature on the Celsius scale. While Fahrenheit scale is not recommended, it is nevertheless widespread and the question arises if there is a widely accepted symbol for the respective quantity.

Yes, it is widespread and, for example, everybody understands what

means. Why is a symbol needed? What equation do you have in mind where it would be useful to have a symbol for temperature expressed in degrees Fahrenheit?

 

[Bystander]

https://www.britannica.com/science/Rankine-temperature-scale

 

[Baluncore]

There are specific symbols used to represent the fahrenheit unit.
https://www.compart.com/en/unicode/U+2109

 

[DaveE]

IUPAC recommends T as the symbol for absolute temperature and t or theta for temperature on the Celsius scale. While Fahrenheit scale is not recommended, it is nevertheless widespread and the question arises if there is a widely accepted symbol for the respective quantity.

Really? Everyone I know uses K, C, or F. often with a superscript ^o.

In my world T would be a variable for temperature which might have a value expressed in one of several different units. Like T = 97^oC, or T = 370K.

The pertinent question is: will your readers be confused by what you write? If you told me the temperature was 14T, I would have no idea what you were referring to. But then I was never any good at chemistry, so YMMV.

 

[Baluncore]

Fahrenheit the person should be capitalised, fahrenheit the unit should not. The abbreviation of fahrenheit should be a capital, F, because the unit is derived from a person's name.

The capital abbreviation, F, should be prefixed by the degree symbol, °F, to differentiate it from the SI unit of capacitance, the farad, F, named after Faraday.

A lower case, f, is the metric prefix for, femto = 10^-15.

 

[DrDu]

Thank you for your answers, I found now that in this IUPAC document .
On p. 138 they use $t_\mathrm{F}$ as symbol for temperature on the Fahrenheit scale.

 

[A.T.]

IUPAC recommends T as the symbol for absolute temperature and t or theta for temperature on the Celsius scale. While Fahrenheit scale is not recommended, it is nevertheless widespread and the question arises if there is a widely accepted symbol for the respective quantity.

Usually you use the same symbol for the quantity and indicate the units in brackets like: v [m/s] or v [km/h].

Of course you can abbreviate that by assigning a single symbol to a combination of quantity and units, but then you have state this explicitly. Otherwise it will be ambiguous, even if there are some widespread conventions in some fields.

 

[DrDu]

Usually you use the same symbol for the quantity and indicate the units in brackets like: v [m/s] or v [km/h].

Of course you can abbreviate that by assigning a single symbol to a combination of quantity and units, but then you have state this explicitly. Otherwise it will be ambiguous, even if there are some widespread conventions in some fields.

This seems at variance with the definition of a physical quantity as, e.g. explained in the document cited above: "The value of a physical quantity Q can be expressed as the product of a numerical value {Q} and a unit [Q] Q = {Q} [Q] (1)Neither the name of the physical quantity, nor the symbol used to denote it, implies a particularchoice of unit (see footnote 1, p. 4)."

 

[sophiecentaur]

, everybody understands what

means.

'everybody`??? I'm more familiar with Gas Mark numbers. Perhaps we should base our Physics on the cookery world.

It would be a good principle to stick to T and K in any Science formulae when possible.

 

[DrDu]

Maybe it is clearest to explain this differently.
The difference between absolute Temperature and Celsius or Fahrenheit is not only a change of units but of scale.
For the Celsius scale we define a new quantity
$$ t =T-T_0,$$
where $T_0=273.16\; \mathrm{K}$. $t$ may perfectly well be reported in Kelvin, but we chose to report it in degrees Celsius, to make clear the change of scale.
Likewise,
$$ t_\mathrm{F}=T-T'_0$$
where $T'_0=255.37\; \mathrm{K}$. We may also report it in Kelvin, but again we usually chose a unit of $1\; ^\circ\mathrm{F}=5/9\; \mathrm{K}$.
Is it absolutely necessary to introduce $t$ and $t_\mathrm{F}$? Probably not, but I think it is helpful.

 

[sophiecentaur]

Maybe it is clearest to explain this differently.
The difference between absolute Temperature and Celsius or Fahrenheit is not only a change of units but of scale.
For the Celsius scale we define a new quantity
$$ t =T-T_0,$$
where $T_0=273.16\; \mathrm{K}$. $t$ may perfectly well be reported in Kelvin, but we chose to report it in degrees Celsius, to make clear the change of scale.
Likewise,
$$ t_\mathrm{F}=T-T'_0$$
where $T'_0=255.37\; \mathrm{K}$. We may also report it in Kelvin, but again we usually chose a unit of $1\; ^\circ\mathrm{F}=5/9\; \mathrm{K}$.
Is it absolutely necessary to introduce $t$ and $t_\mathrm{F}$? Probably not, but I think it is helpful.

Of course I agree but people want to use verbal descriptions and we see, everywhere 'twice the temperature'. A disaster unless they have used K. (and they never have)

 

[DrDu]

It would be a good principle to stick to T and K in any Science formulae when possible.

I wholeheartedly agree. But what do you do if you, for example, expect temperature readings in a clinical study from all over the world? I think you should describe as precisely as possible how to interconvert between different scales as possible, because you can't rely on every data manager knowing how to do this.

 

[sophiecentaur]

expect temperature readings in a clinical study from all over the world?

In that sort of context, you can expect that, if thermodynamics comes into it, it would only come in at the end and the simple initial '9/5-32' formula will bring the data together with no problems. Most clinicians are happy enough with statistics but don't get their hands dirty with actual Physics; they have too much else to worry about.