Metrication

[jakeroot]

One of the biggest arguments in favor of metrication - that it is more efficient for business if the measurements used match those of other countries - doesn't really apply to the US in the same way as it might to somewhere like the Netherlands because the US has 335 million people, more than any other country not named China or India. With 335 million people, we're already a very large market on our own, so there isn't a whole lot of economy of scale benefit to be realized by better synchronizing measurement standards with other countries.

This got me looking into populations of India and China...

* India adopted the metric system in 1956; population 407 million
* China (ROC) adopted the metric system in 1929; population ~475 million
->> China went fully metric only in 1990; population 1.13 billion
* USA's metric board was disbanded in 1982; population 232 million

India had no official measurement system prior to 1956. China's adoption of metric replaced the local shìzhì ("market") measurement system.

In all three cases (India, China, USA), the GDPs have grown no matter which measurement was being used, although certainly India and China both benefited from going metric; China's final push to limit the "market" measurements in the 1980s was likely influenced by economic growth.

My point with this research is simply to highlight that both India and China, at periods in their history when their populations were far larger than even modern day America, were able to adopt metric. Whether the metric system played a role in their economic growth, I could not say. But both likely benefited from a uniform measurement system that matched those countries with which they traded not only goods, but also workers. This is likely where the US would benefit most: people coming to visit or work not being confused by our system of measurements; Americans themselves are unlikely to see any particular benefit...but then that isn't the point per se.



The one annoying thing, honestly? I did not need to learn imperial measurements. If the US adopted metric in the 1980s, we'd be somewhere around halfway to an American population that learned the metric system from birth, rather than incidentally as we aged. But...no. I had to learn some idiotic measurement system because generations of people before me learned it, got used to it, and then forced it on me too.

[Bruce]

The one annoying thing, honestly? I did not need to learn imperial measurements. If the US adopted metric in the 1980s, we'd be somewhere around halfway to an American population that learned the metric system from birth, rather than incidentally as we aged. But...no. I had to learn some idiotic measurement system because generations of people before me learned it, got used to it, and then forced it on me too.

I have a feeling that imperial measurements would still be taught in schools...but in history class. Or for other legacy items that would still carry imperial measurements in their names.

[Brandon]

My point with this research is simply to highlight that India and China, with populations far larger than even the US has today, was able to adopt metric. Whether the metric system played a role in their economic growth, I could not say. But both likely benefited from a uniform measurement system that matched those countries with which they traded not only goods, but also workers. This is likely where the US would benefit most: people coming to visit or work not being confused by our system of measurements; Americans themselves are unlikely to see any particular benefit...but then that isn't the point per se.

The big difference here (and with France in the 18th century) is the lack of an internal system of measurement that is consistent throughout the country.  In France, the foot was different, north versus south.  China and India lacked any coherent internal measurement system.  The US, by contrast, has a consistent internal measurement system, using both customary and SI (with customary, oddly enough, based off SI).

[Rothman]

I'd love to see the regression analysis that isolated the effect of switching to metric had on India and China's economic growth.  You know, how that was what did it and not massive reforms to their governments...

[kalvado]

My point with this research is simply to highlight that India and China, with populations far larger than even the US has today, was able to adopt metric. Whether the metric system played a role in their economic growth, I could not say. But both likely benefited from a uniform measurement system that matched those countries with which they traded not only goods, but also workers. This is likely where the US would benefit most: people coming to visit or work not being confused by our system of measurements; Americans themselves are unlikely to see any particular benefit...but then that isn't the point per se.

The big difference here (and with France in the 18th century) is the lack of an internal system of measurement that is consistent throughout the country.  In France, the foot was different, north versus south.  China and India lacked any coherent internal measurement system.  The US, by contrast, has a consistent internal measurement system, using both customary and SI (with customary, oddly enough, based off SI).

I would assume India used British system during colonial times, making it consistent.
Consistency of US system isn't great, though. Nautical and statue miles, fluid ounces and just ounces can add to confusion.
On the other hand, with more things getting computerized, conversion is often just a press of the button.
Biggest inconsistency I see, though, is in nominally inch based pipe threads. Those, as well as wire gauges, can only be memorized

[1995hoo]

.... There is nothing stopping customary units from being used in-tandem with metric units in everyday life.

....

This is a point I made earlier in the thread. It's not as if you would suddenly throw out your existing cookbooks, recipes, measuring spoons, etc. A tablespoon of salt is still a tablespoon of salt, regardless of whether the container from which you pour it says one pound or 500 g. I have a few recipes set in metric units (primarily ones I found online), so I flip the kitchen scale or the oven display to grams or Celsius for those, and if there's a unit for which I don't have an appropriate measuring cup, I either use a conversion app or I ask Siri to convert it.

[kalvado]

.... There is nothing stopping customary units from being used in-tandem with metric units in everyday life.

....

This is a point I made earlier in the thread. It's not as if you would suddenly throw out your existing cookbooks, recipes, measuring spoons, etc. A tablespoon of salt is still a tablespoon of salt, regardless of whether the container from which you pour it says one pound or 500 g. I have a few recipes set in metric units (primarily ones I found online), so I flip the kitchen scale or the oven display to grams or Celsius for those, and if there's a unit for which I don't have an appropriate measuring cup, I either use a conversion app or I ask Siri to convert it.

In machining, most machines can be switched from metric to inches by a single button. However, step size cannot be totally agnostic to units. Mill I am using once in a while has minimum step of 0.5 mil or 0.01 mm - and I assume it would add or miss a step in one if units. Not the precision I need anyway, but would be a problem for high end machining.

[jakeroot]

My point with this research is simply to highlight that India and China, with populations far larger than even the US has today, was able to adopt metric. Whether the metric system played a role in their economic growth, I could not say. But both likely benefited from a uniform measurement system that matched those countries with which they traded not only goods, but also workers. This is likely where the US would benefit most: people coming to visit or work not being confused by our system of measurements; Americans themselves are unlikely to see any particular benefit...but then that isn't the point per se.

The big difference here (and with France in the 18th century) is the lack of an internal system of measurement that is consistent throughout the country.  In France, the foot was different, north versus south.  China and India lacked any coherent internal measurement system.  The US, by contrast, has a consistent internal measurement system, using both customary and SI (with customary, oddly enough, based off SI).

I think this is exactly why the United States will never go fully metric: US customary units are beautifully coherent and consistent...within the confines of the United States. This does compare quite favorably to many local systems replaced elsewhere by metric. Still, US customary units are (basically) as much a local system as any other local measurement system, and it's only coherent amongst those that actually have learned and actively use it. To the rest of the world (minus a couple exceptions), US customary units are completely incoherent and totally bizarre.

Here in Japan, my knowledge of US customary units is completely worthless. Zero aspects of daily life use anything but metric.

[kalvado]

My point with this research is simply to highlight that India and China, with populations far larger than even the US has today, was able to adopt metric. Whether the metric system played a role in their economic growth, I could not say. But both likely benefited from a uniform measurement system that matched those countries with which they traded not only goods, but also workers. This is likely where the US would benefit most: people coming to visit or work not being confused by our system of measurements; Americans themselves are unlikely to see any particular benefit...but then that isn't the point per se.

The big difference here (and with France in the 18th century) is the lack of an internal system of measurement that is consistent throughout the country.  In France, the foot was different, north versus south.  China and India lacked any coherent internal measurement system.  The US, by contrast, has a consistent internal measurement system, using both customary and SI (with customary, oddly enough, based off SI).

I think this is exactly why the United States will never go fully metric: US customary units are beautifully coherent and consistent...within the confines of the United States. This does compare quite favorably to many local systems replaced elsewhere by metric. Still, US customary units are (basically) as much a local system as any other local measurement system, and it's only coherent amongst those that actually have learned and actively use it. To the rest of the world (minus a couple exceptions), US customary units are completely incoherent and totally bizarre.

Here in Japan, my knowledge of US customary units is completely worthless. Zero aspects of daily life use anything but metric.

Well, sometimes world coherency is required. Cars, even US made, are metric these days. Last time I heard Harley Davidson was the last true-to-inch one.
A fun thing  is how semiconductor wafer size evolved (maybe not a full list, what I saw myself):
2", 3". 4" and 100 mm (only see 100 mm now) , 150mm (6"), 200 mm(8"), 300 mm, (stalled so far) 450 mm.

[jakeroot]

The one annoying thing, honestly? I did not need to learn imperial measurements. If the US adopted metric in the 1980s, we'd be somewhere around halfway to an American population that learned the metric system from birth, rather than incidentally as we aged. But...no. I had to learn some idiotic measurement system because generations of people before me learned it, got used to it, and then forced it on me too.

I have a feeling that imperial measurements would still be taught in schools...but in history class. Or for other legacy items that would still carry imperial measurements in their names.

History class is certainly where it would belong; 95% of the world speaks this one other measurement "language", and a full adoption of the metric system should negate any need to learn US customary units for anything other than being able to communicate with the rest of society that never learned metric.

[hotdogPi]

I will point out that some customary units, typically very small ones, have fallen out of favor and been replaced with metric, even in the US.

A dram is 1/8 fl oz, but anything that small is in mL.

As for non-fluid ounces: the ones we're familiar with don't have anything smaller unless I'm missing something, but troy ounces (used for measuring precious metals) have pennyweights (240 dwt = 1 troy pound, as you would expect if you're familiar with predecimal British currency), and smaller than that, grains (24 to the pennyweight). However, here, anything smaller than 1/4 ounce or so (or even larger if you're reading a nutrition label) is in grams.

As for inches: a pica is 1/12 inch, and a point is 1/72 inch = 1/6 pica. (I've also seen "pixel" for supposedly 1/72, but those are definitely variable.) What we have instead: 0.5, 0.7, and 0.9 mm pencil leads. Even those closer to an inch can be metric: "9 mm" for guns. I have seen mils (1/1000 inch) as thickness of paper, cling wrap, aluminum foil, etc., but only on product labels, not in speech or ordinary writing.



As for "natural" units:
10 in = foot as in part of the body (most feet are smaller than a foot)
1.5 ft = cubit
3 ft = human reach, also the width of a door
5 ft = eye level, horse height, car height
6 ft = human height, also approximately the maximum height you can fall without getting hurt if you intentionally jump down (rather than slipping and falling) and are not versed in parkour
10 ft = ceiling height
12 ft = car length
15 ft = one-story building height including attic

These are all at least somewhat "natural". You can take any length on a human scale and claim it's natural.

[jakeroot]

Well, sometimes world coherency is required. Cars, even US made, are metric these days. Last time I heard Harley Davidson was the last true-to-inch one.

I'm sure a lot of America's daily life is "accidentally" metric. Someone's speedometer may be in miles per hour, the temperate gauge in Fahrenheit, and fuel economy in miles per gallon. But that car was certainly designed in metric units, and the only reason it can display those units is because of the US market.

[kalvado]

I will point out that some customary units, typically very small ones, have fallen out of favor and been replaced with metric, even in the US.

A dram is 1/8 fl oz, but anything that small is in mL.

As for non-fluid ounces: the ones we're familiar with don't have anything smaller unless I'm missing something, but troy ounces (used for measuring precious metals) have pennyweights (240 dwt = 1 troy pound, as you would expect if you're familiar with predecimal British currency), and smaller than that, grains (24 to the pennyweight). However, here, anything smaller than 1/4 ounce or so (or even larger if you're reading a nutrition label) is in grams.

As for inches: a pica is 1/12 inch, and a point is 1/72 inch = 1/6 pica. (I've also seen "pixel" for supposedly 1/72, but those are definitely variable.) What we have instead: 0.5, 0.7, and 0.9 mm pencil leads. Even those closer to an inch can be metric: "9 mm" for guns. I have seen mils (1/1000 inch) as thickness of paper, cling wrap, aluminum foil, etc., but only on product labels, not in speech or ordinary writing.



As for "natural" units:
10 in = foot as in part of the body (most feet are smaller than a foot)
1.5 ft = cubit
3 ft = human reach, also the width of a door
5 ft = eye level, horse height, car height
6 ft = human height, also approximately the maximum height you can fall without getting hurt if you intentionally jump down (rather than slipping and falling) and are not versed in parkour
10 ft = ceiling height
12 ft = car length
15 ft = one-story building height including attic

These are all at least somewhat "natural". You can take any length on a human scale and claim it's natural.

Machinists actively use "mills" - 1/1000 inch.

[kalvado]

Well, sometimes world coherency is required. Cars, even US made, are metric these days. Last time I heard Harley Davidson was the last true-to-inch one.

I'm sure a lot of America's daily life is "accidentally" metric. Someone's speedometer may be in miles per hour, the temperate gauge in Fahrenheit, and fuel economy in miles per gallon. But that car was certainly designed in metric units, and the only reason it can display those units is because of the US market.

That's exactly what I mean by "conversion by one button"
It can be implemented better or worse though. My home thermostat offers 1F or 0.5C temperature setpoints. Except for 19 to 20C, where it skips a point to align two scales.
Same with one machine at the gym, where weights are in lbs, and rounded to nearest kg skipping some points.

[GaryV]

fuel economy in miles per gallon

That's required by law and regulation.

Incidentally, the metric version of fuel economy is in inverse units to the English/American units - liters per 100 km. The lower you get, the better.

[kalvado]

fuel economy in miles per gallon

That's required by law and regulation.

Incidentally, the metric version of fuel economy is in inverse units to the English/American units - liters per 100 km. The lower you get, the better.

All this doesn't tell you how things are designed. Internal unit of speed may very well be  "wheel RPM" and distance - "number of wheel turns", with normalization coefficients to human readable miles or km.
Yes, US legislation is written in US units mostly. Doesn't preclude using watts in energy efficiency laws - instead of BTU or therms. There are error bars on most (all? I saw only the document covering retail sales,, but there may be more)  of those values defined by NIST, and those are surprisingly large. So legal  conversion may be pretty lousy.

[1995hoo]

.... the decimeter has always felt like a redheaded step child.

....

Just because you heard the word "decimeter" in school as a kid doesn't mean anyone actually uses it. I don't think I've ever seen that unit used in real life. (For obvious reasons, the kiloliter is not something ordinary people encounter either–if you took the familiar 2 L soda bottle, for example, a kL would be the equivalent of 500 bottles.) The mere fact that there are units that aren't used often by ordinary people, or that are particularly large or particularly small or rather esoteric, is not a valid argument against a particular system of measurement–if it were, then the US measurement system would suffer from the same failing when you consider seldom-used units like leagues (these days used mainly in fiction writing), rods, or furlongs (used primarily in horse racing).

[Big John]

In engineering school, only groups that were 3 apart were recognized for metric measurement, i,e, micrometers, millimeters, meters, kilometers.  In-between units were not to be used.

[bandit957]

If the metric system is based on 10, why are its time measurements based on 60?

[1995hoo]

If the metric system is based on 10, why are its time measurements based on 60?

The French attempted to redefine time to use base 10. It didn't work too well.

[kalvado]

If the metric system is based on 10, why are its time measurements based on 60?

Because those are way older than metric system. Day was divided into 24 parts in Babylon.
Actually second is the only true metric unit of time.

[Scott5114]

As for inches: a pica is 1/12 inch, and a point is 1/72 inch = 1/6 pica. (I've also seen "pixel" for supposedly 1/72, but those are definitely variable.) ... I have seen mils (1/1000 inch) as thickness of paper, cling wrap, aluminum foil, etc., but only on product labels, not in speech or ordinary writing.

All of these are still used in the printing industry–points are the unit that the font size drop down in your word processor are set to (theoretically a font size of 72 will get you 1-inch text). Picas are I believe used in page layout in things like newspapers. Mils are used to measure the thickness of non-paper printing substrates (the last run of playing cards I printed, the standard plastic thicknesses available were 10 mil and 15 mil, but I had to custom-order some 13 mil to get the right feel).

[GaryV]

All of these are still used in the printing industry—points are the unit that the font size drop down in your word processor are set to (theoretically a font size of 72 will get you 1-inch text).

Almost. The 72 points, 1 inch, is measured from the top of the letters in one line to the top of the letters in the next line. I.e., it includes the spacing between the 2 lines.

Speaking of printing, the weight of paper is expressed in pounds. It's how much a ream (500 sheets) of the paper would weigh. But paper comes in various standard sizes. 20 pound bond is based on 500 sheets of 17x22 inch paper. Other stock sizes are much larger, such as index which has a basis of 25.5 x 30.5 inches, so the pound weight is much higher, 67 and 75 pound.

They all have metric equivalents, gram per square meter, which means the relative weight of each type of paper can be directly compared.

[Road Hog]

All of these are still used in the printing industry–points are the unit that the font size drop down in your word processor are set to (theoretically a font size of 72 will get you 1-inch text).

Almost. The 72 points, 1 inch, is measured from the top of the letters in one line to the top of the letters in the next line. I.e., it includes the spacing between the 2 lines.

I used to paginate and that is true, but other factors to account for include descenders where you need to nudge text at least 6 pt of space (I used 7). There are 12 points in a pica and 6 picas in an inch. I avoided heds of greater than 48p unless it was a power hed.

[US 89]

I am of the opinion that there shouldn't be any issue with having multiple measurement systems out there.

But maybe that's because I am a meteorologist, where customary and metric units both see a huge amount of use depending on what quantity you're talking about and what it is you're measuring. Meteorology is perhaps one of the most confusing fields in this regard, because you have to give your output in a form that the people reading it are going to be able to understand. If you're making a public forecast in the US, that means customary units. If you're in research or around scientists from other fields, almost entirely metric. But the #1 application is aviation, which was a huge influence on the development of the field as a whole, and so a lot of their preferred units carried over. And sometimes what's used is simply a matter of what looks good on a map.

Just to get an idea of the huge variety of units and systems we use regularly in American meteorology:

Temperature - Fahrenheit for surface temperature, Celsius for anything upper air. For any sort of thermodynamics equations, we'll use Kelvin, which sometimes gets converted back to Celsius and sometimes does not. I can convert C to F and vice versa to within a degree or two in my head very quickly because I have a bunch of equalities memorized beyond just the freezing/boiling points: 50F=10C, 77F=25C, 104F=40C, etc...

Speed - miles per hour when talking about surface wind that's going to affect populated places that aren't airports. Pure science contexts will use meters per second everywhere. Otherwise, the general unit of wind speed is the knot, which is equal to a nautical mile per hour and was the usual aviation unit before being essentially adopted by most aspects of meteorology. 1 kt is a little more than a mph, and 2 kt is about 1 m/s. I have no concept for how fast a km/hr is.

Height - usually in meters, unless you're talking about snow levels, which are usually in feet because they reference surrounding topography and we usually think of topographic elevation in customary. Stuff like the height of cloud tops or cloud bases are also often in feet because that's what the aviation industry likes. Even at the international scale today, they prefer to measure height in hundreds of feet. Sometimes you'll get decameters because that requires one less digit on an upper-air map when you're rounding to the nearest 10 m anyway.

Horizontal distance - for visibility, statute miles, or feet if you're talking about visual range on a runway in highly impaired visibility conditions. Nautical miles for hurricanes or aviation - a nautical mile is a little more than a regular statute mile, and is supposed to be the distance covered by a minute of latitude (1/60th of a degree) at constant longitude. Kilometers in more pure science contexts.

Pressure - The usual unit in almost all contexts is the millibar, which the general public only seems to ever hear about when the news is talking about hurricanes. In more pure science you'll usually hear of a hectopascal, which it turns out is exactly equal to a millibar by definition, but because the pascal is the official SI unit of pressure it's considered more acceptable to use that name for those contexts. Might be one of the only actual uses for the hecto- SI prefix. In rare cases you might hear of kilopascals. You’ve probably seen inches of mercury on weather reports, but nobody in the field actually uses them…except our good old friends in aviation, who use it to set their altimeters. There’s likely issues with updating instruments or technology in older planes that make metricating altimeter setting a tall order in the US, but I have no concept for what anything in inHg is and I hate when displays make you use them if you want other units to be in customary.

And the list goes on...