re. the OP
Klickage!
Well, “mileage” is distance measured in miles, and “acreage” is area measured in acres. So, given that the metric unit of area is the are, then something measured in ares would be . . . um, an “area”.
Hectareage?
Damn. I totally messed that up. Everywhere I wrote km/100 Litre, it is really L/100km.
Sorry. Less unique without the stupid errors…,
Whether you actually measure it in ares or not. Multiple languages happen to use the same word for “area” and for “are”, anyway: that’s how the unit of measure came by its name.
The basic issue seems to be how different culture/education systems teach handling physical quantities and/vs. units.
In one of the first lessons when we first had physics, as a separate subject, in German Gymnasium (IIRRC it was in 5th form), the teacher rammed home the following concept:
Never talk about “how many kilograms, how many meters, how many litres” etc.
Talk about the physical quantities - mass, length, volume, instead.
The names of the quantities don’t have the units in them for a reason - you can measure them in different units but the quantity stays the same.
Quantities and units are different things and should be kept separate.
This is why e.g. in German
voltage is elektrische Spannung - no volts in that
amperage is Stromstärke - no amperes in that
acreage is Fläche - no unit in that either.
mileage [fuel consumption] is Kraftstoffverbrauch
mileage [odometer indication] is Tachometerstand or Fahrleistung
I wonder if this system is actually more widespread in other languages (it seems to be in French), and the concept of incorporating an unit into the quantity name is actually an exception internationally.
For example voltage = tension électrique, tensión eléctrica, elektrische Spannung, tensione elettrica, elektrisk spænding, электри́ческое напряже́ние, elektrische spanning, gerilim etc. - no volts in sight except in English.
This is theoretically… well, arguably true, I guess, but do people think this way? Does anyone look at MPG and think “well, thank God, I buy 500 gallonbs of gas a year and now I can drive further?”
MY guess is basically no one thinks that at all, ever. For that matter, living in Canada, do you think I looked at the l/100km number and thought about how many litres of gas I’d have to buy? Of course not; to be honest, I am not exactly sure how far my drive to work is or how much I drive in terms of errands and such. What matters is how the number compares to other cars. If it’s MPG, I know that a car that has the number “40” is better than one with the number “35.” The former car will be cheaper to drive. (I am ignoring the highway/city distinction for simplicity.) If we’re talking l/100km, 7.9 is better than 9.1. I don’t really give a crap what the numbers mean, and I suspect most people think the way I do. What matters is how they compare to one another. All other things being equal, the car with the better number - higher if it’s distance-per-volume, lower if it’s volume-per-distance - is going to save me money.
You could devise any number of ways to express fuel efficiency, I suppose. All I car about is what that number is relative to competing models of car.
But as I initially pointed out in #53, and others have echoed, that isn’t the point. The point is that if you’re comparing cars that have, say, a 5 mpg difference in stated fuel consumption, that same 5 mpg is going to equate to dramatically different actual fuel consumption for any fixed distance traveled. In a sense you’re right that it doesn’t matter what the numbers actually mean, but it does matter that l/100 km (or gallons/100 miles) are numbers that scale linearly with real-life fuel consumption across a broad range of fuel efficiencies. A difference of, say, 5 l/100 km is the same difference in cost to travel a given distance whether you’re talking about a motorcycle or a train locomotive, but a difference of 5 mpg varies tremendously among vehicles of different fuel efficencies in terms of what it costs to travel a given distance. That’s why the EPA in the US is now also quoting gallons/100 miles in addition to the standard MPG. MPG differences can be deceptive.
Spanish does sometimes refer to tensión as voltaje, but with a different usage: we’ll say that a machine takes a voltaje of 120 or 210, or that a line has* alto voltaje*. Voltaje refers more to the result of the actual measurement, whereas tensión refers to the different electrical potential and corriente eléctrica to the “zipping about of electrons” you get once you close the circuit.