
The Argument of Twelves and the Metric System - rienbdj
https://milebehind.wordpress.com/2019/08/06/the-argument-of-twelves-and-the-metric-system/
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Animats
The real problem is that it's bad for US exports. Outside the US, almost
nobody has inch tools.

US defense, aviation, and automotive have been metric for decades now.
Electronics still has some inch stuff in through-hole parts.

US construction, though, is still inch-oriented.

Home Depot stocks few metric fasteners. I had a conversation there with
someone from a restaurant who was desperately trying to get the fasteners
needed to fix some piece of metric equipment on a weekend. Home Depot didn't
even have basic metric screws.

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aviation_
US Aviation in the sense of the "aero" part of aerospace is still very much US
Customary Units. I don't have enough experience with the "space" part of
aerospace to comment on that. We still use pounds of thrust, slug and pound
masses, psi for pressures and so on for things related to turbines and engines
and so on. Strangely, we use kelvins instead of Rankines but that's the only
exception I can think of.

Edit: Note that this isn't to say that aerospace engineers prefer the US units
or that we don't know how to use the metric system or anything, it's just how
it is. In this particular field, it's just the accepted standard.

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naval-gazer
In Aviation there are nautical miles for ground distance, knots for speed and
feet for altitude. But in US aviation there are also statute miles for airport
visibility and feet for runway visibility.

Customary units are bigger mess than imperial vs. metric.

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bnegreve
Nautical miles make some sense because they are consistent with the lat./long.
coordinate system (60 miles = 1° lat). For the rest, I'm not sure.

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newscracker
Would it be 60 miles for 1° in all locations for the latitude, considering
that the earth is an ellipsoid/spheroid?

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simonblack
Latitude is measured along a Great Circle of Longitude - confusing isn't it?
So the distance between (say) 10 and 30 degrees North is the same as the
distance between 50 and 70 degrees North.

The Latitude circles (in the 'horizontal' plane) get smaller as you go from
Equator to the Poles, but all the Longitude Circles (in the 'vertical' plane')
are all Great Circles and go through both the North and South Poles and so are
all (pretty much) equal in size.

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Aardwolf
Optimally humanity should have chosen base 12 instead of base 10, then the
metric system would have used it :)

But anyway, to me it doesn't actually matter.

Admittedly I don't do workshop stuff that much, but when I do, I measure with
a ruler, and never needed fractions for that, numbers like 3.333 work fine.

Where do you need fractions if you've got floating point notation, plus if
you'd like to use fractions nothing stops you from saying "1 third of a
meter".

And the imperial system doesn't really use base 12 much anyway? The only ratio
of 12 I see in there is inch and foot. All the rest is various random
different ratios (e.g. a mile is 5280 foot? really? and gallon vs ounce is a
ratio of 160?), and Fahrenheit is its own separate mess.

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masklinn
> All the rest is various random different ratios (e.g. a mile is 5280 foot?
> really? and gallon vs ounce is a ratio of 160?)

TBF you're skipping intermediate units. After all 12^3 would be 1728 so non-
decimal units quick get to weird ratios.

Of course you're also right that imperial and customary measurements use
seemingly random ratios even within the same unit of measure: the mile is 5280
feet because a statute mile is 8 furlong, a furlong is 10 chains, a chain is
22 yards (though technically there's the intermediate "rod" unit which is
1/4th of a chain, and thus 5 ½ yards) and a yard is 3ft.

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mkl
In base 12, 12^3 = 1000. Easy! Base 12 numbers and base 12 "metric" would be
great, but unfortunately we will never have them.

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ginko
I think one thing that's often glossed over in the imperial vs metric
discussion is that users of metric almost universally stick to decimal
numbers, while fractions are a lot more commonly used with imperial. For many
Europeans, dealing with values like 3/8 or 5/16 seems completely unintuitive
and even deciding which of them is larger will take us some thinking. So being
able to elegantly converting fractions seems like a non-issue since you would
never use them in the first place.

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DiogenesKynikos
One place where the metric/American mixup is a regular pain is paper sizes.
American scientific journals are generally published on Letter paper, while
all other scientific journals are generally published on A4 paper. The
difference in aspect ratio is just enough to cause the bottoms or sides of
pages to be cut off if you don't pay attention.

One nice thing about the international paper standard is its subdivision
property: if you fold a piece of paper in half (along the correct axis), it
retains its aspect ratio. That's pretty useful for printing pages 2-up, and
for reducing paper waste. It's a similar argument to the "argument of
twelves," but it goes in the opposite direction: the metric standard is
favored.

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masklinn
TBF you've got to be slightly obsessed to see the metrication in A-series:
most people will interact with A3 and A4 papers which are respectively
420x297mm and 297x210mm, if you go up you end up with A0's 1189x841mm which
doesn't look very metric either. You've got to realise that it's 1 sqm in a
sqrt(2) ratio to see the metrication (the aspect ratio being chosen so it
stays constant when you halve the page through its larger edge).

The B series actually looks "more metric" at first glance: B0 is 1414x1000mm.

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shmerl
People like what they are used to, so they can be simply defending the habit.
US should be pushing more strongly to switch to metric system instead of
dragging this for ages. Speed signs should use kilometers per hour, and
weather reports should use Celsius.

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NeedMoreTea
It's 50 years, maybe a little more, since Britain required all education to be
in SI units. That's two generations taught entirely metric. Weather has been
in Celsius only for almost as long.

People still mostly refer to their height in feet & inches, buy a pint of
beer, but petrol's in litres, they drive at 40 mph, and calculate mpg. When
it's cold most people use Celsius, but when it's hot, people always remember
Fahrenheit and it's 80s, 90s, etc. Never quite worked that one out. :)

It's going to take a bloody long while, whenever the switch starts, whether it
includes road signage or not.

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jobigoud
> buy a pint of beer,

This is not really a problem I think. It's become an object in itself and you
don't really use this as a reference when buying milk or water I imagine. In
France you can also get a "pinte" of beer (pronounced as "paint"), it's
probably a relic from before the metric system and probably not the same as
the English pint though.

Celsius vs Fahrenheit is tricky because Fahrenheit does have some nice
properties and several sciences use Kelvin anyway. I think the best one would
be a new one, rescaled to match with 0°C and 100°F.

Calculating mpg is an interesting one because even if you moved to calculating
km per liters it would still doesn't match the most common usage, we use
liters per 100 km.

One thing where almost everyone fails in my opinion is shoe sizes. Why can't
we just use centimeters? Instead we have four competing standards and the EU
one doesn't relate to anything.

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Throw_Away_5374
> Fahrenheit does have some nice properties

Which exactly? Walter melting at 0°C and boiling at 100°C seems the most
practical.

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jobigoud
The main niceties are the increased granularity (nobody would use half °C in
practice) and 100°F being the normal body temperature and a good landmark to
relate to hot weather.

0°C is absolutely super practical and is imperative to have as a landmark.
100°C boiling water... it isn't really that practical in day to day use in my
opinion (when was the last time you saw 100°C written on a device?). In the
high temperatures the ones I care about in a practical sense are on the oven
for cooking and on my soldering station, both much higher than 100°C anyway.
The only time I care about boiling water temperature is when I am boiling
water in which case I don't need a thermometer.

So I think 100°F is more interesting as a landmark than 100°C for intuiting
temperatures. You can think of it as the percentage of how hot it is. But 0°C
is more interesting than 0°F.

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StavrosK
I don't understand why we want round numbers here. I know 40 C is "very hot"
and for Americans that's 100 F. Using a rounder number makes absolutely no
difference, since I'm never going to divide temperatures.

It doesn't even matter much for meters and kilometers, since I very rarely
need to talk about things that are kilometers away and meters away in the same
context. It's handy to have sane units for those, though, since there you
_can_ multiply and divide in your calculations.

Temperature arguments never seemed particularly compelling to me. They assume
100 is more convenient, which I find wrong, since you're usually talking about
102, 86, 95, etc anyway.

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w1nst0nsm1th
The only things Americans get right is dollars and interest rates.

I would not go as far as to say it probably means something but here we are...
:)

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martyalain
I just discover your submission and - if you can read french - I wonder what
you could think of this paper :
[http://marty.alain.free.fr/confs_2019/?view=grain](http://marty.alain.free.fr/confs_2019/?view=grain)
where I try to use the imperial system [foot,inch]] inside the metric system.

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kasperni
The site ahead contains malware Attackers currently on marty.alain.free.fr
might attempt to install dangerous programs....

on Chrome

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realusername
Same on Firefox, it's probably blacklisted in the safe browsing list.

