Comment by kbenson | Hacker News Reader

Comment by kbenson | Hacker News Reader

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There are actual benefits to some imperial units when working in small amounts. They can often be subdivided much more easily into amounts that are harder to handle (or at least require going to another order of magnitude to do accurately).

For example, dividing a foot into thirds or fourths is trivial, but for a meter it requires either going two orders of magnitude (25/100ths for a quarter) or simply cannot perfectly represent the amount (1/3).

Now, not all imperial units have sane definitions, and they don't even all follow similar rules (8 fluid oz. to a cup, 16 fluid ozz to a pint, you lose thirds but can still easily do fourths).

In a lot of ways, base 10 is really substandard to base 12, we just used base 10 because it's physically easy and socially ingrained. Who knows, maybe 100 years from now we'll teach in base 12 and have a new system that's base 12, and all the metric die-hards will been seen as backwards yokels that cling to a clearly substandard system because of history and it's what they know? I mean, I really, really doubt it, but it would be better than the metric system as long as most people could easily think in base 12 (which would require a massive social upheaval).

"It cannot perfectly represent the amount" you say, and then perfectly represent the amount.

You represent a quarter as the fraction 25/100ths to show how impractical it is, instead of writing 1/4.

Would it be so hard to build a ruler with thirds measured on it, so you don't need to try and guess 0.333333 from mm readings? Like http://teaching.monster.com/nfs/teaching/attachment_images/0... but made of metal

> "It cannot perfectly represent the amount" you say, and then perfectly represent the amount.

Actually, I said "It cannot perfectly represent the amount (1/3)", so I specifically game an example immediately after the statement of exactly what I was talking about, which you then ignored and used an example for a different item to represent erroneously. What's up with that?

> You represent a quarter as the fraction 25/100ths to show how impractical it is, instead of writing 1/4.

No, I represent a quarter as 25/100's to show how it would be accurately represented in metric. 1/4 meter is not pure metric, it's applying a non-metric modifuer to a metric amount. The metric representation of 1/4 meters is 25 centimeters, which is 25/100.

Let me lay it out side by side:

- 1 and 1/2 units Imperial: 1 foot 6 inches or 18 inches Metric: 1 meter 50 centimeters or 15 decimeters or 150 centimeters

- 1 and 1/3 units Imperial: 1 foot four inches or 16 inches Metric: 1 meter 33 centimetersa and 3 millimeters and... or 133.33... centimeters

- 1 and 1/4 units Imperial: 1 foot 3 inches or 15 inches. Metric: 1 meter 25 centimeters or 125 centimeters

That's not to say imperial units are good. They are hard to use for most things because they change across types of things measures, and counting in twelfths when needed is much more painful than in tenths.

But, if we were taught in a 12 base system we would be able to use it easily, and base 12 has more cases where it can be used easily than base 10. Everything else would be the same except than our sense of scale would be a little different and we would have an easier tome subdividing things in many cases.

Metric isn't an optimal system, it's just the optimal system for right now and the world we currently live in. But for a few historical turns of fate, it might have been very different.

> Would it be so hard to build a ruler with thirds measured on it, so you don't need to try and guess 0.333333 from mm readings? Like http://teaching.monster.com/nfs/teaching/attachment_images/0.... but made of metal

Then it's not metric. That's the point. We use these values anyway, yet you have to step outside the metric system to represent them easily. Adding extra marks that don't correspond to the regular intervals is confusing, so it's avoided. That's why most rulers in the united states show metric on one side and imperial on the other.[1]

1: http://cdn.dickblick.com/items/554/27/55427-1012-3ww-l.jpg

>No, I represent a quarter as 25/100's to show how it would be accurately represented in metric. 1/4 meter is not pure metric, it's applying a non-metric modifuer to a metric amount. The metric representation of 1/4 meters is 25 centimeters, which is 25/100.

What? Fractions aren't exclusive to the imperial system.

1/4 of a metre is metric, just as a 1/4 of an inch is imperial.

Everything below is a perfectly legitimate way of writing metric units:

1/4 m = 6/24 m = 3/12 m = 0.25 m = 25 cm = 250 mm

So easy!

Fractions are mathematical modifiers that can applied to any quantifiable measurement. That said, I imagine they aren't generally used in professional context in metric, because they generally aren't in imperial either. You don't see architectural plans that say 1-1/2 feet, they say 1'-6". Is it common to see fractional amounts in metric when used in a professional context?

Usually we write everything in mm for professional context.

Thanks, that's what I assumed (because it makes sense). For metric you often go two orders of magnitude smaller, but I'm thinking a good amount of the reason to usually go straight to millimeters instead of also using decimeters is that decimeters just can't easily represent many common fractions of a meter (1/4, 3/4, 1/3, 2/3), and a base 10 system can never represent some of those perfectly without resorting to a mixed format.

Buy an imperial rule.

There's some inches that are sub-divided into tenths (maybe 1/20), and others sub-divided into sixteenths (maybe 32nds or 64ths). Often with heavier markings on more significance. For easy division and fractioning of whatever it is you are doing.

If it's imperial only (v. rare nowadays) there's usually a coarser scale or two for easier subdivision or when the 16ths and finer just don't matter.

Buy a metric rule.

There's mm, cm, and metres. Nowt else, not even weighting of marks except usually 1cm or 5mm. For measurement this is fine. For division such as in woodwork, metalwork and building, this is often a pain in the ass.

Metric only usually engraves just one side or exactly duplicates. No coarser scales.

So even when working in metric I often find an older imperial rule a better working tool(!)

How often is the distance you need to divide a whole number of inches anyway?

No more often than it is a multiple of 12mm, 60mm, or whatever.

Real distances are either designed for easy calculation, like my N*150mm kitchen pieces, or are some random length.

As someone who does a lot of woodworking in a metric world: the common fractions (e.g. 1/3) are not a problem at all, they are periodic. Adjusting my saw to 333.33mm or 6.66mm is something I do quite often.

If you use fractions often or work with weirder fractions anybody who is worth their grain of salt will build custom temporary rulers or helper systems anyways. And then it won't matter at all if your unit is hyperinches or fractions of lightspeed traveling through frozen beer in a second.

I can see how anybody who grew up with inches likes that one better, but in the end it is just numbers on a scale.

> If you use fractions often or work with weirder fractions anybody who is worth their grain of salt will build custom temporary rulers or helper systems anyways.

My point is a system with less need for that because it can handle more common divisions easily would be good.

> I can see how anybody who grew up with inches likes that one better

I tried to be very explicit in that I was not promoting the imperial system. I'm not even promoting imperial distance over metric distance. I'm purely using feet because there's a base 13 for inches to illustrate how a full base 12 system might work. Feet and inches are much worse than metric even in this case because that conversion only happens at one spot, not at regular orders of magnitude.

All I was saying is that since it's a fact there are some things that can be done in base 12 that can't be done in base 10 but not the other way aroubd, it would be really interesting (and extremely unlikely) if we somehow shifted to a base 12 metric-like system. That wouldn't be imperial (which has a different conversion every time you blink).

I learned a lesson though. People are very protective of the metric system. Even opining about fictional future possibilities with mathematical facts will lead to downvoting into oblivion and people misinterpreting clear assertions as something they aren't.

> My point is a system with less need for that because it can handle more common divisions easily would be good.

My point was, that from a practicle standpoint this doesn't really matter. If you need to tick of a third of a meter somewhere just a few times, everybody would just happily make a mark at 333.33mm – if you need to do this 50 times, building a temporary ruler is a good idea in any measurment system, because it reduces both cognitive load and the likelyhood of mismeasurement. This is especially true if you are building something that involves many steps that are repetitive, similar, but different enough to ruin your day if you fuck up.

For me one of the best things about the metric system is, that it in fact is base10 because it eases the conversion and calculation between units and has cool effects that imo outwheigh the cool things you would get from going base12.

Going base12 in a good way would mean going base12 fully, including temperatures, currencies, voltages, weight, etc. and this would mean turning a whole culture of knowledge upside down and inside out. If we would have a world dictator they might try something like this. From a distribution perspective it is desirable to have one standardized unit system that makes sense.

So my pain point isn't exactly metric vs imperial, but that in 2018 we still need to deal with these two systems and the conversion between them. Metric is far more wide spread than imperial and this has reasons, some historical, some political, some practical. If you are one who thinks national unilateralisms are a waste of energy and potential, you are certainly in favour of the metric system, just because it would be easier for the world to agree on going fully metric, than it would be for the world to go fully imperial.

And I am not talking about everybody having to use it in their day to day life – just look at the UK. I am talking about certain space agencies, industry, electrical engineering etc, where these things can have real graspable consequences, maybe even deaths.

That's actually my point. Whilst I use metric for almost all things, an imperial rule is, for me, a better temporary custom rule for actually doing stuff like centre finding or sub-dividing, than the metric ones. The units don't matter a jot, the markings and spacings do.

Which is why I keep one of each in the tool chest. :)

> but for a meter it requires either going two orders of magnitude (25/100ths for a quarter) or simply cannot perfectly represent the amount (1/3).

What? you switch to metric and suddenly fractions are not a thing any more?

1/3 m is just that, one third of a meter, perfectly. How is that so complicated? It can also be 333.3mm. And no one would write it as 333/1000 to make it seem more complicated than it is.

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