The SI base unit for mass is actually the kilogram. It is memorable and notable for being the only base unit that already has a prefix.
> the only base unit that already has a prefix.
That is interesting. So is kg actually not designed to work with other prefixes? Is it supposed to be megakilogram vs gigagram? Or are you just supposed to convert to something else or always use scientific notation? Or am I right about gigagram being valid, but for the wrong reasons?
Gigagram just seems exotic in the same way that megameter does - it's perfectly correct and understandable, it's just rarely necessary.
https://en.m.wikipedia.org/wiki/Centimetre%E2%80%93gram%E2%8...
I suspect this is because, sort of like length, there's many different names for essentailly different orders of magnitude and you'd first go to the largest (a tonne, 1000 kg) before adding on prefixes. I suspect this many-names factor is in turn because they're such historical things that humans have measured and quantified since prehistory, because distance and mass are the first 'quantities' we begin to encounter.
So instead of 793 gigagrams, I'd say 793 thousand tonnes, or 793 kilotonnes.
Also common: micrograms and microliters.
Per my latter comment, it's because we don't really deal with everyday words for masses smaller than a gram, but we do for those bigger. It still holds that as far as I can think, people will go to the closest 'common term' word and then use prefixes to bridge the remaining gap (milligram, megatonne)
Also, 'liter' is used only in the US I believe. You guys just won't play with the other children, huh. :-)
edit: ah ok sorry NamTaf. Get some sleep!
[1] https://www.duden.de/suchen/dudenonline/Liter
[2] http://slovniky.korpus.sk/?w=liter
I think it's the same in Slovenian, Hungarian, Serbian (litar?), Norwegian and Swedish.
As an mechanical engineer educated in the UK the base unit would be kg but you would use ax10^n [kg] to denote mass.
This question of whether there's a meaningful send in which the base unit is the kilogram and not the gram really confuses people and I don't know what the answer is. People eagerly proclaim (a) it has something to do with French historical convention (but, they admit when pressed, this gives it no non-trivial meaning today) or (b) it has to do with the size of the actual reference weight in France (which doesn't make sense because the second was never an object, and a meter no longer is represented by an object yet we still call it a base unit).
The only non-trivial interpretation I've heard (although it is still silly) is that the kilogram is the base unit in the sense that adding "kilo" to gram makes the derived units like the Newton the simplest. (You could define a Newton in terms of grams and, say, kilometers and seconds, or meters and milliseconds, but this would end up disturbing the other derived units even worse.) But of course, this is just a statement about the derived units.
"The kilogram is the International System of Units (SI) unit for mass. It is the only remaining base unit to be defined by a physical object. All standards of mass must ultimately be traceable to this one object, a cylinder of platinum-iridium alloy kept at the International Bureau of Weights and Measures (BIPM) in France"
If the President issues a statement that says "the base unit of the US is the furlong", but nothing else about the US or its system of measurements changes, this is a contentless statement. If someone else asks "but what does it actually mean for the furlong, as opposed to the inch, to be the base unit?", pointing them to the President's statement does not help.
(Remember, saying "the kilogram is the base unit" cannot refer to the fact that the mass object in France weighs a kilogram, not a gram, because people also say "the meter and the second are base units", neither of which are physically instantiated anywhere.)
Love the last paragraph:
The decision of the Republican government may have been politically motivated; after all, these were the same people who condemned Lavoisier to the guillotine. In any case, we are now stuck with the infelicity of a base unit whose name has a "prefix".