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# Imperial versus metric

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On 1/5/2023 at 4:23 AM, Kerbart said:

The issue with the US sticking to imperial measurements is not that (as much as it does) imperial has shortcomings; it's that the rest of the world doesn't use it. That's where conversion errors come from. ATC doesn't have that problem; everyone; everyone, worldwide, uses nautical miles for distance and feet for altitude. As long as you're all using the same units, there's not an issue. Switching to metric wouldn't really have benefits, be a gigantic operation and arguably be unsafe.

International trade is a good example. Everyone agrees on the length of a standard container; it's 40 foot*. Nobody calls that a 12.19m container and no one is insane enough to demand that the standard size should be 12m; Everyone agrees on the same unit, 40', and little need to switch (Ironically, temperature for reefer containers is set in Celsius, not Fahrenheit. Once in a while you'll have an American shipper learn that lesson with a container full of rotten meat).

* Yes, there are 20' containers, and 45' containers and occasionally a few 53' containers will make their way across the Pacific, but by far the most prolific size is 40'

If you want to order a beer there's not an issue, you're right. It's only an issue if you want to calculate with formulas. And then it's a huge issue.

Let's take Newtons F = m * a as example. In SI simply put your mass and the local gravitational acceleration in SI units in (kg and m/s^2), and you get the force in SI unit (N) which pulls you to the ground after the 5th beer when visiting Munichs Oktoberfest (I can tell). Easy as cake. When working with formulas you do not have to care about units at all. That's quite nice.

What conversions factors (or even offsets) do you need in imperial units for even that simple (but magnificent) formula ? And more complex formulas quickly become a nightmare in Non-SI- units.

And it's only a small number of units you have to know in the SI system. One can scale it easily with base 10 prefixes (as mm, cm, km and so on based on the meter e.g.) . Degree Celsius (no SI unit, but commonly used in Europe) is a little bit a special case, but its only an offset to the Kelvin scale. But nearly nobody knows the Kelvin as temperature unit in Europe ("Ah, do you mean Calvin and Hobbes?") . And a liter of beer (1l = 1/1000 m^3) is also nice. Cheers ! Tom

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Well, in UK they not only use pint on beer, but also in the milk.

For a while it was difficult to explain to my parents how much milk I was drinking in a day.

"Around... a pint... maybe?" "Human language please."

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11 hours ago, Deddly said:

Ah yes, the beauty of the imperial system, where the US pint does not match the UK pint (just one example).

Sigh. I want to burn this whole system with fire.

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46 minutes ago, RCgothic said:

Sigh. I want to burn this whole system with fire.

Just wait a little.

Spoiler

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2 hours ago, RCgothic said:

Sigh. I want to burn this whole system with fire.

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7 hours ago, TomKerbal said:

If you want to order a beer there's not an issue, you're right. It's only an issue if you want to calculate with formulas. And then it's a huge issue.

Let's take Newtons F = m * a as example. In SI simply put your mass and the local gravitational acceleration in SI units in (kg and m/s^2), and you get the force in SI unit (N) which pulls you to the ground after the 5th beer when visiting Munichs Oktoberfest (I can tell). Easy as cake. When working with formulas you do not have to care about units at all. That's quite nice.

What conversions factors (or even offsets) do you need in imperial units for even that simple (but magnificent) formula ? And more complex formulas quickly become a nightmare in Non-SI- units.

And it's only a small number of units you have to know in the SI system. One can scale it easily with base 10 prefixes (as mm, cm, km and so on based on the meter e.g.) . Degree Celsius (no SI unit, but commonly used in Europe) is a little bit a special case, but its only an offset to the Kelvin scale. But nearly nobody knows the Kelvin as temperature unit in Europe ("Ah, do you mean Calvin and Hobbes?") . And a liter of beer (1l = 1/1000 m^3) is also nice. Cheers ! Tom

Those are valid points but they only apply to a very small segment of the population, it's not going to sway the 95% who in their daily life just have to deal with basic units. I agree that working with pound forces and weird conversion factors (how many inches are there in a mile? I know right away that there are 100,000 cm in a km) is at best inconvenient and a great way to ask for errors. And in the fields that are affected by it, to my knowledge, a lot of work is done in SI units because it's so much easier (and less error prone) and then simply translated to freedom units where required.

Even then, if (god forbid) the entire world was using imperial, as attractive as the decimal system is, it would be extremely hard to switch over. Rationale and "it makes sense" won't cut it if you're the only one using the better system (there's proof in mathematics for this).

Throw in unrational arguments ("it's un-American", "How inconvenient to ask for a 5.08×10.16 at home depot, inches are clearly much easier," "express a mile in feet and I can divide it by every prime you can think of", "metric is science") and it's clear that we're not going to see it change anytime soon. Switching over is more a social issue than anything else, and engineers and scientists are notoriously bad at figuring out how to make that work.

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6 hours ago, kerbiloid said:

Just wait a little.

Hide contents

OH COOL, titan will be habitable!

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On 12/30/2013 at 2:23 AM, Brotoro said:

You wouldn't be doing anything as absurd as using 60 minutes in an hour, 24 hours in a day, or 7 days in a week would you? My gosh...how do you survive?? And I'd hate to think how many radii fit around the circumference of your circles. Hopefully you've managed to make that come out to ten as well for peace of mind.

I really hope you can see that measuring days, months and years using the orbits of the Earth and the Moon is not as absurd as using imperial for no other reason than "it was there, I guess".

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18 minutes ago, Bej Kerman said:

I really hope you can see that measuring days, months and years using the orbits of the Earth and the Moon is not as absurd as using imperial for no other reason than "it was there, I guess".

Who needs those orbits?!

The real value is rather obvious.

Quote

The second [...] is defined by taking the fixed numerical value of the caesium frequency, ΔνCs, the unperturbed ground-state hyperfine transition frequency of the caesium 133 atom, to be 9192631770 when expressed in the unit Hz, which is equal to s−1

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8 hours ago, Bej Kerman said:

I really hope you can see that measuring days, months and years using the orbits of the Earth and the Moon is not as absurd as using imperial for no other reason than "it was there, I guess".

I didn't say anything against using days or months or years. I spoke about dividing days arbitrarily into 24 hours, and hours into 60 minutes, and blocking days into arbitrary 7-day weeks... which people manage to deal with even though those aren't powers of ten.

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Posted (edited)

Time is divided in circles, as well as angles.

So, while counting things and money is arbitrary, the dial must be able to be divided in as much integer parts as possible.
Thus, 12/24/60/360 is absolutely natural for the time and angles.
(I presume, the °F scale was originally based on some arrow rotating from up to down, so it's 180-based.)

Though, I believe it would be better to use 6/12-base numeric system rather than 10, with 72 or 144 cm in 1 m.

P.S.
Why do the Imperials not rename "foot" into "boot"?

30.48 cm, seriously? Of the shortest NBA players?

30.48 is a boot size.
From memory, "Take sixteen men, short and tall ones, when they, say, are getting out from the church, take their boots and put in a raw. Measure the raw with a rope, and use one sixteenth of it as a 'foot'."

Edited by kerbiloid
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One problem I see impeding the conversion to metric is the fact that it (in some cases) is a system designed to be universal, but does not take into account that some measurements 'make more sense' in other units.  It is an arbitrary system of units (aren't they all?), which has been imposed on a variety of industries, regardless of wether it is actually convenient or not.

To be clear, I do think most people (including myself) see an enormous benefit to having a single standardized measurement system.  However, in some cases there is not a clear benefit to using SI units, aside from the standardization issue.  This point is probably going to enrage SI fans, but I ask that you bear with me.  If you truly want the world to convert to your way of thinking, it might be helpful to understand your opponent's point of view.  (And not just insult them..)

I use both Imperial and SI units, and don't really care which units are used, as long as the units are specified.  However, this thread has made me consider which units I have switched over to preferring SI for, and why.

I'll start with baking bread.  I used to use Imperial units, such as cups and tablespoons to measure both dry material and liquid.  However, for dry material (flour, salt, etc.) it makes much more sense to use weight (or mass) to accurately measure.  Grams or kilograms are convenient units to use, equally manageable to ounces or pounds.  I started weighing my dry ingredients in grams (SI).  At that point, it made sense to also measure liquids in SI as well, in mL or L.  For baking, I've been converted.  I use SI.

However, when it comes to cooking I do not find SI units convenient.  I'll use an example of preparing a batch of Hamburger Helper for a family of 4.  A typical meal would use 1 pound (lb.) of hamburger.  One pound is a meal.  How much is that in kg?  0.45 kg.  That's a subtle point, but I'm hoping the SI fans will see the difference.  I need one meal.  I get 1 pound of meat.

Let's take that a step further.  I have two teenagers in the house.  I add 50% to everything.  Now I need 1.5 pounds of meat.  If I was working with SI, I would have to take 150% of 0.45 kg.  Yes, I'm ok with math, I need to add 0.225 kg to my original 0.45 kg.  So now I need 0.675 kg of meat.  But using pounds the math was much easier.  So while I use SI for baking now, I still prefer Imperial for cooking.  And that does indeed bother me somewhat.

Why can't I use SI for all my food preparation?  Well, the answer is, I can!  But it does not necessarily make sense to do so, at least not to me.

In a bizarre world, let's say that somebody decided that for consistency the entire world needed to use Imperial units for everything.  For folks who prefer SI, how would that make you feel, to have Imperial units forced on you?  If everyone used imperial units, there would no longer be issues with consistency, everyone would be using the same units, just like they are with SI.  (Yes, I do understand that Imperial units are in some cases FAR from consistent.).  My point is that I do agree with the concept of a worldwide standard of measurement, which is SI.  However, that does not, in my mind, mean that other measurements are inferior or need to be eliminated.

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Posted (edited)
On 1/5/2023 at 6:23 AM, Kerbart said:

everyone; everyone, worldwide, uses nautical miles for distance and feet for altitude.

Soviet / Russian aviation uses metric units, except on the bought/rented planes. Only meters and kilometers.

On 1/5/2023 at 6:23 AM, Kerbart said:

Everyone agrees on the length of a standard container; it's 40 foot*. Nobody calls that a 12.19m container and no one is insane enough to demand that the standard size should be 12m

And these containers have different actual sizes, so '40 foot (feet) ' is just a callname based on their historically adopted normative length.

1 hour ago, 18Watt said:

One problem I see impeding the conversion to metric is the fact that it (in some cases) is a system designed to be universal, but does not take into account that some measurements 'make more sense' in other units.  It is an arbitrary system of units (aren't they all?), which has been imposed on a variety of industries, regardless of wether it is actually convenient or not.

It's first of all decimal, i.e. uses same numeric base for all units, not "12 hyrs = 37 chpunks = 11 3/4 tsiflings"

While the "Imperial" is exactly the latter.

1 hour ago, 18Watt said:

I used to use Imperial units, such as cups and tablespoons to measure both dry material and liquid.

Say, in Russia, a vodka bottle is 500 ml (champagne 750 ml), a glass is  200 ml (sometimes 180), spoons are from 5 ml (tea spoon) to 20 ml (soup spoon), etc. And nobody even in nightmare would deal with pints and quarts.

So, measuring powders as liquids doesn't depend on units.

1 hour ago, 18Watt said:

However, for dry material (flour, salt, etc.) it makes much more sense to use weight (or mass) to accurately measure.

Not necessary. They can be dry or wet, have various grain size and density, so unless you bake a whole lot of bread in a bakery, it's as good and more simple to measure their volume.

So, the home recipes say "take 50 g of butter, a glass of flour, salt on the knife point".

1 hour ago, 18Watt said:

A typical meal would use 1 pound (lb.) of hamburger.

A half-kilo of meat. Only nerds can quickly say, what is "pound", 453.6 g. Others operate with grams/kilograms.

Nobody would weight a pound for you, take 500 g and feel free to cut off 46.4 g at home.

1 hour ago, 18Watt said:

Now I need 1.5 pounds of meat.

What's the "pound"?
750 g of meat, or even 700 g, but the salesman would look at you as at a strange cheapskate and ask "Maybe a kilo?".
Everyone would think "Poor thing, he counts every kopeck."
If you ask for 675 g everyone in the foodstore will be sure that you are trolling the salesman, and you have a chance to know a lot of info about yourself.

1 hour ago, 18Watt said:

Why can't I use SI for all my food preparation?

Because your kitchen stuff is in wrong, obsolete numbers.

Buy the normal, metric one, and you will be squirming when a recipe is in pounds.

1 hour ago, 18Watt said:

In a bizarre world, let's say that somebody decided that for consistency the entire world needed to use Imperial units for everything.

It was so in early XX. And even more, every country had its own pounds. Say, the Russian pound was 409 g.
Everyone (well, except several post-British states) turned to SI.

1 hour ago, 18Watt said:

For folks who prefer SI, how would that make you feel, to have Imperial units forced on you?  If everyone used imperial units, there would no longer be issues with consistency, everyone would be using the same units, just like they are with SI.

What about USD consisting of 20 shillings, each of 12 pence? And 1 guinea = 21 shilling.
THAT is Imperial, not those rebels' "100 cents".

Edited by kerbiloid
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I said it earlier in the thread but it bears repeating: I have personally transitioned from all imperial measurements (UK) to metric. It took me a few weeks maybe to be able to visualise a kilometre, a litre, a centimetre etc., but I was surprised how easy it was to make the change. I can't ever imagine going back.

Moving to metric is an inconvenience, but once you're there, you wonder why you didn't do it sooner.

Like @kerbiloid says, metric works just as well for visualising things as imperial. 750 g of meat is no more complicated to work work with than 1.5 lb. It's a bit like switching from driving on the left to driving on the right. Neither system is wrong, but it makes a lot of sense to just bite the bullet and do what everyone else is doing.

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Everything about metric is great, except the base 10. Base 10 was a mistake. 2 and 5 are just not great factors to work with if that's all you've got, and being able to quickly scale things is the whole point. Two quick alternatives come to mind. First option, keep it simple, doubling only. That gives you 1024 as an increment very close to 1000 we're already using. Works great in computing - we'd just have to implement everywhere else. The only downside is that "A third of a meter" is still an awkward quantity, and we're as far from metric time as we have always been.

Second option is to keep compounding factors. 12/60 works great for time and angles, but it's good for distances too. You can say all you want for yards and feet not making sense with larger units, but on the human scale, a third of a foot is 4 inches, and not some nonsense. Full circle being 360 degrees was a miss, though. We should make it 420 degrees. Now we have a factor of 7 in there as well. With another doubling we pick up divisibility by 8, and 840 is also in the ballpark of 1,000, making it another candidate for a better kilo- prefix.

It is tempting to pick up another 3, to have divisibility by all factors in 1-10 (I mean, I don't expect the base 10 numbering system to go away, sadly.), but 2520 might be a bit too far from a thousand. It'd be a big change. So we'll probably have to just live with only divisibility by factors in 1-8.

But if we do take kilo = 840, we can add prefixes for intermediate fractions. Like, one septantkilometer is 120 meters. Simple, convenient, neat. And we can fold the clock and the calendar into this system without too many problems, because now we have all these additional factors to work with. Take the minute as the new base unit, and now a second is just a sexagintiminute, an hour is a hexecontaminute, and a week is a septuagintimegaminute. Or dodecakilominute, if you prefer. Perfect system. 10/10. No notes.

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Posted (edited)

Well, the SI system is now not only purely scientific origin, I would not say. A meter is about an arm's length, a second about a heartbeat and a kilogram (based originally on the original kilogram in Paris) should probably correspond pretty much to 1 liter (=1/1000 m^3) of water. One meter, about one step. That's probably where this originally came from and was then taken as the basis for a consistent system of units, the SI system. And exactly, man has 10 fingers, normally ;-)
24 hours each 60 minutes each 60s has the day, because it probably fits well integer with previously defined second (so well that only every 4 years is a leap year) I could imagine. One could have taken also 10 hours with 864 minutes per 10 seconds :-) But you can not count so well.
Unfortunately, many non-SI units are also used in our country (felt more and more). For example, there are different "inch" units (screens, pipes), miles (nautical and whatever). Extremely confusing.

Edited by TomKerbal
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4 hours ago, TomKerbal said:

Well, the SI system is now not only purely scientific origin, I would not say. A meter is about an arm's length

I don't know what you're talking about. A meter is precisely the distance traveled by light in 656616555/21413747ths of a hyperfine structure transition cycle of a Cesium 133 atom. Look at all these digits. You can't get more scientific than that.

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I think evolving with 10 digits on our hands was the first mistake. We should have evolved 12 then we could all use a duodecimal counting system and so many of these problems would have been avoided.

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So, the root of evil is in the human evolution. Humans should have six fingers per hand.

Humans should be genetically modified. Two thumbs and four others.
Thus you can use both duodecimal and octal systems.

Also it's useful to have additional buttons on mice and switches on rifles.

***

A calendar-related question.

What are proper English terms for idle days? Are they holidays?

1. Saturday / Sunday - a "holiday" or what?

2. Xmas or another such day of a year - a "holiday" or what?

3., An unexpected/planned day when you are free of work and stay at home - a "holiday" or what?

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14 minutes ago, kerbiloid said:

What are proper English terms for idle days? Are they holidays?

1. Saturday / Sunday - a "holiday" or what?

2. Xmas or another such day of a year - a "holiday" or what?

3., An unexpected/planned day when you are free of work and stay at home - a "holiday" or what?

In US English, at least, people don't usually use the word "holiday" for Saturday/Sunday outside of religious contexts. (E.g. Sabbath) The typical word used is "weekend". The word "holiday" is, indeed, used for things like Christmas, New Year, Thanksgiving, etc. But that word can be used even if you don't get days off.

The term "vacation", while primarily used for planned time away from work can still occasionally be used even if it's unplanned. The general catch-all is "time off" or "day off". That can be used to describe vacation, holidays when you're not working, and any other day you simply don't have to work. Weekends aren't typically called days off, unless there's a specific reason why you'd need to highlight that you don't work on the weekend, such as if you work in retail or service where your schedule may include weekends in general.

I believe, Canadian and UK English tend to use similar terminology, but there could be regional variations there that I'm not familiar with, and outside of these three, I have no idea.

Thank you.

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UK English we don't normally use the word vacation so a holiday is either a day of the year with a specific name, Christmas, good Friday, August bank holiday etc or something you plan for that involves leaving your home.

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Posted (edited)
On 1/7/2023 at 1:15 PM, K^2 said:

Everything about metric is great, except the base 10. Base 10 was a mistake. 2 and 5 are just not great factors to work with if that's all you've got, and being able to quickly scale things is the whole point.

I don't really get the fascination with scaling down by fractions. In practice, very few situations actually call for it. How often do you need to start with an even meter or a kilogram and split it equally into three? Whether it's cooking, science, or construction, the measurement you start with is rarely exactly one unit.

Edited by Codraroll
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4 hours ago, Codraroll said:

How often do you need to start with an even meter or a kilogram and split it equally into three? Whether it's cooking, science, or construction, the measurement you start with is rarely exactly one unit.

Even if rounding, it's way more precise to round once. What's a third of 1.15kg? Do you round it to 1kg, take a 3rd and call it 300g? But the real answer is closer to 400g. The relative error is now 22% instead of 13% on first rounding.

If you wanted to take a 3rd of 1.15ft, and call it 4", that's the same 13% error you got from rounding to a foot.

Of course, you can work around it with slightly more complex arithmetics, but everything else being the same, having more factors helps make it easier and less error-prone.

That said, without also changing the counting base, there are limits to utility, and I hope it's clear I'm being facetious with some examples.

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13 hours ago, K^2 said:

I don't know what you're talking about. A meter is precisely the distance traveled by light in 656616555/21413747ths of a hyperfine structure transition cycle of a Cesium 133 atom. Look at all these digits. You can't get more scientific than that.

Exactly :-)

That's what I meant. Otherwise it had perhaps been defined as 1/300 000 000 * c0 * 1s . Its origin is a handy unit afterwards taken into a very scientific system you are absolutely right.

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