Conversion Error

FTR, in this classic article http://www.straightdope.com/classics/a1_127.html Cecil cough I mean Cecil’s editors screwed up the conversion between Celsius and Kelvin.

I believe the article should read either 276 degrees Kelvin or -270 Celsius.

I’m suspect that the second is correct.

It’s not outright wrong. Three degrees Kelvin is indeed 3 degrees above absolute zero. It’s a bit confusing to use the unit “Celsius” when referring to a temperature difference, but I can’t see any way around it if you want to distinguish it between F and C/K.

I believe that it should read “3 Celsius degrees (5 F degrees)”, where you are talking about the size of the degrees and not absolute temperature–which is clearly what was intended.

I disagree that the column is wrong, or even confusing. “…the equivalent of 3 degrees Celsius… above absolute zero.” Looks OK to me. Why is it confusing to use the unit “Celsius” when referring to a temperature difference? If it’s 20 degrees Celsius inside my home, and 5 degrees Celsius outside, just how would I express the difference, if not “15 degrees Celsius”?

RM Mentock: You sure? I’ve never heard of a differentiation in unit usage between an absolute measurement and differences. I went looking, and the only usage note reference I can find which explicitly calls out a temperature difference (as opposed to absolute measurement) is here: “The unit of Celsius temperature is the degree Celsius, symbol ºC, which is by definition equal in magnitude to the kelvin. A difference of temperature may be expressed in kelvin or degrees Celsius. [bolding mine]”

I think scr4 has it right. I missed the “above absolute zero”.

If I’d read more carefully I’d have to agree with zut that it is not even confusing.

I’d carelessly read that 3C == 3K, which, of course, the article did not say.

Sorry for the distraction.

Thanks all,

Tinker

…and hang your head in shame for even THINKING that Cecil could commit an error.

Never sure, but Physics at Oklahome State seems to thinks so: “Notice that we write temperature difference in terms of Celcius degrees (C°) instead of degrees Celcius (°C)”. Hmm, not sure if there are other usage notes anywhere…

Cecil is not totally wrong, but one thing does come to mind…

The unit KELVIN is a stand-alone unit of temperature measurement. Meaning, that the Kelvin value does not require a “degrees” or “°” pre-fix. We use the term Kelvin as 273 Kelvin or 11 Kelvin (cryogenic vacuum pump second stage temperature).

Otherwise, Cecil, keep up the good word !!
Scott

Well, I did blame the editors … :o

Degrees Kelvin and degrees Celcius are the same in magintude only.

-273 C = 0 K

The same holds true for American Standard measurements, Rankine and Fahrenheit degrees are equal in magnitude.

-(five hundred and change, I don’t remember)F = 0 R

Cecil got nothing wrong here, as far as I can tell.

Uh, please ignore the above post.

It’s pretty useless.

I don’t know what I was thinking.