Flaws with the Metric System

[Raphael]

Anyway, Darren's mention of Top Gear made me wonder: has usage in car-related contexts led to any Brits or other Commonwealth people using US gallons for some purposes?

[Zju]

Before I read your post, I didn't even know about the m/M distinction, and I've used the metric system for all my life.. And how does the sign in the photo you posted cause confusion? What else could "KM" mean in that context?

Sure, it's clear for "KM", but what about "MG"? Does it mean milligram or megagram?

Whoever uses megagram at all, let alone regularly? Besides, I've never seen milligram abbreviated as MG, only ever mg.

[Raphael]

Before I read your post, I didn't even know about the m/M distinction, and I've used the metric system for all my life.. And how does the sign in the photo you posted cause confusion? What else could "KM" mean in that context?

Sure, it's clear for "KM", but what about "MG"? Does it mean milligram or megagram?

Whoever uses megagram at all, let alone regularly? Besides, I've never seen milligram abbreviated as MG, only ever mg.

jcb seems to approach the Metric System the way you might approach a programming language, and is therefore appalled by minor details most people won't ever notice, like the uppercase/lowercase thing.

[Moose-tache]

Europeans attacking Imperial measurements: "Oh, you need to know the body temperature of a horse? Or the legnth of a barleycorn? Don't you see that your system is absurd on a technical level? Try solving for X using only furlongs, you Medievalist!"

Europeans defending Metric measurements: "Look, it's good enough, OK. Convention and familiarity make any technical flaws irrelevant. You're just being pedantic and nit-picky. Honestly, I don't know why you're thinking about it so hard."

[Zju]

Americans attacking Metric measurements: "Why can't I use a nice whole number below 10 for THAT particular everyday item? Ugh, what a dealbreaker!"

Americans defending Imperial measurements: "To convert from dorths to shmogadiboos you only have to divide by 17. It's simple, really!"

[Travis B.]

even when outside of them (e.g. in scientific and engineering contexts) I favor Celsius.

In scientific and engineering contexts, you should use Kelvin!

Well yes, but it's harder to remember or picture temps in that rather than Kelvin.

0 degrees F is a completely irrelevant, arbitrary temperature to me, far colder than anything I have ever experienced living on two continents. Literally nothing happens when you cross that temperature.

Exactly, that's why the argument that Fahrenheit "is more human relevant" never makes sense to me.

Here Fahrenheit is perfect, because it practically always stays right in the range 0-100 F except on the most bitterly cold days of January, where it may go a bit under 0 F.

[Raphael]

Here Fahrenheit is perfect, because it practically always stays right in the range 0-100 F except on the most bitterly cold days of January, where it may go a bit under 0 F.

But why should it stay always in the 0-100 range? Knowing instantly whether it's above or below freezing based on whether it's above or below zero is simply useful, IMO.

[Travis B.]

Here Fahrenheit is perfect, because it practically always stays right in the range 0-100 F except on the most bitterly cold days of January, where it may go a bit under 0 F.

But why should it stay always in the 0-100 range? Knowing instantly whether it's above or below freezing based on whether it's above or below zero is simply useful, IMO.

The thing is everyone knows that 32 F is freezing, and it easily gets below freezing here, whereas it practically never gets above 100 F (but it can get into the 90's F), making that a good upper limit.

[KathTheDragon]

It's more precise and the 0 and 100 points are more human-relevant.

... So?

Seriously. Americans always say things like this but I don't see why it matters any.

Look, both systems work in practice just fine for the people who are accustomed to using them. But if asked to choose between the two, I will choose the one that I already (primarily) use, and have the bonus of knowing that it is more precise and makes more practical everyday use of numbers spanning the 0-100 range.

I wouldn't dream of forcing you to use Fahrenheit. But there are occasional calls for the US to abandon it, and I'm happy to explain why I say no to them.

I'm asking why it should matter. Please explain, I am fascinated to know why you care about "precision".

[Ares Land]

I've said it before, but the only reasonable option is Planck units.
The only downside is with the basic unit for temperature at 1,417 * 10^32 K we may lose a bit of precision. But just remember the freezing point of water is at 1.928 * 10^-30 and you're all set.

[äreo]

... So?

Seriously. Americans always say things like this but I don't see why it matters any.

Look, both systems work in practice just fine for the people who are accustomed to using them. But if asked to choose between the two, I will choose the one that I already (primarily) use, and have the bonus of knowing that it is more precise and makes more practical everyday use of numbers spanning the 0-100 range.

I wouldn't dream of forcing you to use Fahrenheit. But there are occasional calls for the US to abandon it, and I'm happy to explain why I say no to them.

I'm asking why it should matter. Please explain, I am fascinated to know why you care about "precision".

Imagine a temperature scale that sets the freezing point of water at -5 and the boiling point of water at 5. Imagine that you had to explain to someone using this scale why you prefer Celsius.

You would undoubtedly mention that Celsius offers greater precision at the integer level. Compared to Celsius, using this 5-to-5 system without resorting to decimals feels like using Pirahã to talk about math.

So at some level, "precision" becomes something you care about. Now the difference in precision between Fahrenheit and Celsius is not nearly as great as the difference between Celsius and some 11-point scale. And since you and most of the world are already using Celsius with no issue, you couldn't care less.

That's fine. But since I already use Fahrenheit by default, its greater precision is something I feel the loss of on the occasions I use Celsius. And I don't make these comparisons to say that Celsius is somehow a bad system. It's a very useful and reasonable system--but Fahrenheit is, to me, just a little bit better.

[KathTheDragon]

You would undoubtedly mention that Celsius offers greater precision at the integer level. Compared to Celsius, using this 5-to-5 system without resorting to decimals feels like using Pirahã to talk about math.

Ah, yes, "undoubtedly" being a word which here means "not consider it worth doing". I don't really have a problem adding an extra digit of precision to make useful contrasts. But also a 10-fold scale difference is hardly comparable to a 1.8-fold scale difference, where the smaller scale is still precise enough to offer useful contrasts at differences of 1 unit.

[äreo]

You would undoubtedly mention that Celsius offers greater precision at the integer level. Compared to Celsius, using this 5-to-5 system without resorting to decimals feels like using Pirahã to talk about math.

Ah, yes, "undoubtedly" being a word which here means "not consider it worth doing". I don't really have a problem adding an extra digit of precision to make useful contrasts. But also a 10-fold scale difference is hardly comparable to a 1.8-fold scale difference, where the smaller scale is still precise enough to offer useful contrasts at differences of 1 unit.

That is why I said:

Now the difference in precision between Fahrenheit and Celsius is not nearly as great as the difference between Celsius and some 11-point scale. And since you and most of the world are already using Celsius with no issue, you couldn't care less. That's fine.

I acknowledge that it is not a matter of great magnitude, but just enough for me to notice the difference and prefer the one I already use. QED

[zompist]

I'm asking why it should matter. Please explain, I am fascinated to know why you care about "precision".

It's been explained several times, but since you're attached to your traditional, arbitrary, non-metric system you find defenses of someone else's traditional, arbitrary, non-metric system baffling. I'm pretty sure that in any other context you would not be so precious and parochial.

If you have a volume knob, it's better that it goes from 1 to 10 than from 4.2348 to 4.2349. If you can't imagine why, please don't design any UIs.

[Travis B.]

If you have a volume knob, it's better that it goes from 1 to 10 than from 4.2348 to 4.2349. If you can't imagine why, please don't design any UIs.

This is also a good argument for why we don't measure temperature in metric units.

[zompist]

If you have a volume knob, it's better that it goes from 1 to 10 than from 4.2348 to 4.2349. If you can't imagine why, please don't design any UIs.

This is also a good argument for why we don't measure temperature in metric units.

Which I already made earlier.

In case it wasn't clear, Celsius is not the SI temperature scale, Kelvin is.

To two digits of accuracy, it's usually about 285 K in London..

[sasasha]

So, sidestepping some of this discussion, I like the idea of the metric system in terms of compatibility, easy conversion and regular naming strategies; but it bugs me that it's baselined on measurements as enormous as the size of the earth. I get that it's (relatively) constant, but I wish the base units were in general more relateable to everyday use. Bring back cubits, I say...

Even if we did though, what could one use as a constant to measure that length? Maybe a conculture could use a statue which can be cast multiple times, for reference. It's probably easier, after all, than measuring the planet you're standing on.

(After a little research, I think the base unit of length measurement should be the height of an average head. Adults will roughly be between 6 and 8 heads tall. 5 heads is about shoulder height, or the height of an outstretched arm, and thus a useful measurement. 10 heads is roughly how far an adult can reach on their tip-toes, or the height of the topmost useful shelves for adults of average height. A head is roughly a forearm, too, which is roughly a step, taken at a slow pace. 100 heads would be roughly 18 metres, and 1000 heads roughly 1.8km, which feels ok for measuring distance and is obviously relateable in concept to the mile. To go the other way, you could say there were ten ‘eyes’ (in height) to the head. This is all obviously slightly arbitrary and potentially sounds a bit ableist!, but as a lighthearted suggestion I do find it less arbitrary than a division of the circumference of the planet.)

[zompist]

Even if we did though, what could one use as a constant to measure that length? Maybe a conculture could use a statue which can be cast multiple times, for reference. It's probably easier, after all, than measuring the planet you're standing on.

Well, they did get it wrong. The polar circumference of the Earth is supposed to be 40,000 km, but it's actually 40,007.863 km.

[sasasha]

Even if we did though, what could one use as a constant to measure that length? Maybe a conculture could use a statue which can be cast multiple times, for reference. It's probably easier, after all, than measuring the planet you're standing on.

Well, they did get it wrong. The polar circumference of the Earth is supposed to be 40,000 km, but it's actually 40,007.863 km.

Ah! Imbeciles. I know I could measure my planet more accurately than that!

[sasasha]

Anyway, Darren's mention of Top Gear made me wonder: has usage in car-related contexts led to any Brits or other Commonwealth people using US gallons for some purposes?

Not in my experience. Not even always for fuel, anymore. People talk about litres of petrol. (But still miles per gallon.)

I've never used a gallon for anything other than fuel, which I can't see the quantity of, so I have literally no idea what one looks like.

In fact, in British kidsplay, a gallon is a very large amount of usually a desirable liquid. So I was very surprised to learn it's not, in fact, a huge vat of something.