In German: 1st version!

First version in English as well.

http://www.bartleby.com/64/C004/016.html gives you 15 °C.

http://www.tastschreiben.de/p0400090.htm

siehe Punkt 8.1: 15 °C (nach DIN 5008)

It seems we get conflicting information for both languages ;)

(meaning: there's probably no single correct way)

Also zumindest in Deutschland ist das ganz offiziell per DIN geregelt (DIN 5008: Schreib- und Gestaltungsregeln für die Textverarbeitung).

Ziehe meinen Beitrag zurück und schließe mich der Gegenpartei an!

Or maybe there is a consensus?: 15 °C

A third option. The author instructions from the journal "Development" states: "Type a space between a digit and a unit e.g. 1 mM (except 1%, 4°C)."

Agree with Sharon. (Welcome, BTW! (-: )

English traditionally requires a space before the unit if it is an alphabetic abbreviation, but not before a nonalphabetic symbol such as º (degrees), % (percent), ' (foot/feet), or " (inch/inches). (And also not before K meaning kilobytes; there may be other exceptions.)

35 mm, 100 kg, 55 mph
98.6ºF, 100%, 256K, 5'10"

"For two or more quantities, the abbreviation or symbol is repeated if it is closed up to the number but not if it is separated.
"35%-50%, 10ºC-15ºC, 6 5/8" x 9", 2 x 5 cm"
-- Chicago Manual, 15th ed.

Anyone regularly working with technical content like this should probably consider investing in a scientific style guide such as the CBE Manual/Scientific Style and Format.

@ hm -- us:

K ist die Abkürzung für Kelvin (Temperatur). Also müsste es 256 K heißen. Die Abkürzung für Kilobytes ist eher kB (im Gegensatz zu Kilobits = kb). kB und kb sind m.W. nicht normiert, weshalb hier allerlei Varianten zu finden sind: kbit, kbits, KB, K, ...

BTW: 1 kB = 1024 B und 1 kb = 1024 kb im Gegensatz zu z.B. 1 kg = 1000 g.

@Markus: Yes, K is *also* the abbreviation for Kelvin, which is why I specifically mentioned kilobytes. It's ambiguous. (Not unlike your signature, BTW: Markus <de>? MarkusW? ??? *g*) If both units appeared in the same text, kB would probably be used instead. But, fortunately, in most cases the issue simply doesn't arise, as the meaning is readily apparent from context.

Maybe it's illogical that K meaning kilobytes should be written without a space before it, but that's just the way it is. Who knows, omitting the space might even have been a necessary step in order to differentiate from K meaning Kelvin, which, unlike every other scale of temperature, illogically fails to use the symbol º or the word 'degrees.' In any case, both are now exceptions to the normal pattern.

It may redeem the logic a bit if we consider that, in practice, K often now simply means 'a thousand,' with the unit omitted/understood. In technical contexts, it's units such as 'bytes' or even 'bytes per second' (a 56K modem); in financial ones, units such as 'dollars' (a 300K salary). So if we think of it as a symbol for a number, rather than as an alphabetic abbreviation for a unit, leaving out the space is more logical after all.

>1 kb = 1024 kb

Ahh. Thanks for sharing that. Maybe that's why I never much liked science. Poetry just makes so much more sense. (-;

Warum K ohne °?

Kelvin ist eine Einheit wie Meter, Sekunde, ..., während sich °C, °F, °R jeweils auf eine Temperaturskala" bezieht, die von den Herren Celsius, Fahrenheit, Réaumur festgelegt wurden. Sie geben dabei an, wieviel Untereinheiten (Grad) eine Temperatur auf den von ihnen festgelegten Skalen entspricht.

@hm--us: no, Markus' post wasn't mine (Markus<de>), but I happily add to the confusion *ggg*
1 Kb = 1024 bytes (capital K denotes dual system, 2^10)
1 kb = 1000 bytes (small k denotes metric/decimal system, 10^3)
Both are used, especially with mass storage (ie hard disc) capacity figures. Check the remarks at the bottom of the backside of the next Dell or HP advertising flyer you can get your hands on ;o)

@Markus <de>: I didn't think it was you, but thanks ever so much for adding to the confusion. *g* Speaking of confusion, I'm clinging to my antique Gateway/Windows 98 as long as possible and keeping my hands off all advertising to the contrary. I hate buying cars and computers, and I've heard such bad things about Windows XP that I may even go back to Apple next, who knows. I have quite fond memories of my 1985 Mac.

I understand, I believe, that in computers (when you say 'dual' I think 'binary?') sometimes 1 [something] = 1024 [something smaller]. (@WH: I still don't understand *why* Kelvin is a unit and not a degree, but I can live without total enlightenment.)

However, it remains news to me that '1 kb = 1024 kb [sic].' Though this general principle would undoubtedly have made math more entertaining. (-;

@hm--us: binary, of course, not dual (BTW: did you know that there a 10 kinds of people, those who understand binary and those who don't? *g*)

and yes, '1 kb = 1024 kb' is news for me, too ... but hey, *some* marketing guy of *some* hardware discounter *will* adopt this equation, no doubt.

to get back on topic: Kelvin is a unit by definition. The international council that watches over the physical unit system (Systeme internationale d'Unitee, Paris, France) found a rather complicated definition and thats it :o)

Es heißt (international) 15 °C, aber: 15° (wenn kein "C" verwendet wird). Die absolute Temperatur wird in Kelvin angegeben und nicht in "Grad Kelvin", daher: 300 K, und nicht 300 °K.

Perhaps Kibibytes will catch on someday -- not to mention Mebibytes, Gigibytes and Tebibytes.

Oops. "Gibibytes"!