[usrbinbash]

> Also, all measurement systems are functionally arbitrary

It's not a question whether they are arbitrary, it's a question if they are technically consistent within themselves.

The metric system is: Everything is orders of magnitude, powers of ten, throughout all the measurements. Consequently, everything measured by base units of distance and mass follows the same rules: A Watt is 1 Joule per second, which is 1 Newtonmeter per second, which is 1 kilogramm per meter squared per second per second per second. 1 Grey (Gy) is 1 Joule of radiation absorbed in 1 kg of mass. If I have to do a calculation, I simply put the different weights and whatever in, and everything just falls into place on its own.

Additionally, measurements of distance and mass are not independent, but based on one another, also by powers of ten. 1000 cubic centimeters (a litre) of Water at maximum density is 1kg of mass. 1 Millilitre of it is 1 gram of mass. 1 m³ of it is 1 metric ton, which is 1000 kg.

Not only is that consistent, it also fits into our radix 10 numerical system like a hand into a fine glove.

I have yet to find any internal consistency in the various imperial systems of measurement. Everything is based on yet another arbitrary comparison with real life objects or references, and so nothing is consistent with anything else. A mile is 8 furlongs, a furlong is 10 chains, a chain is 4 rods, a rod is 5.5 yards, a yard is 3 feet, a foot is 12 inches. Land is measured in acres, which is a furlong by a chain.

Measurements of mass don't follow measurements of distance. A ton is 160 stone, or 160 * 8 "hundredweights", or 160 * 8 * 14 pounds, or 160 * 8 * 14 * 16 ounces. Not only is it not dependent on the distance measurements, the conversion rates are also dissimilar.

[saalweachter]

> Measurements of mass don't follow measurements of distance. A ton is 160 stone, or 160 * 8 "hundredweights", or 160 * 8 * 14 pounds, or 160 * 8 * 14 * 16 ounces. Not only is it not dependent on the distance measurements, the conversion rates are also dissimilar.

Woah woah woah, don't put that evil on us in the USA, that stone madness is all British.

A US hundredweight is 100 lbs.

The metric system didn't invent water volume and weight correspondence -- a pint's a pound the whole world round. 1 pint of water weighs one pound, and one fluid ounce of water weighs one ounce.

[usrbinbash]

> Woah woah woah, don't put that evil on us in the USA, that stone madness is all British.

> A US hundredweight is 100 lbs.

The fact that there are more than one sort of imperial measurements, and that they are different, makes matters worse, rather than better. The metric system works the same, everywhere, in all countries, and in all languages. The only thing that changed since its inception, was switching from defining base units through comparison to physical templates, to defining them by natural universal constants, aka. making it even better than it already was.

> The metric system didn't invent water volume and weight correspondence

I didn't say it did, I said they depend on one another. And in metric, that works for ALL weights and measurements, and does so consistently. Cool, so 1 pint of water == 1 pound. How much is a pint in cubic inches? How many cubic furlongs of water do I need for 10 imperial Tons?

Oh, and btw.: What exactly do you mean when you say "pint"? Because there are many different ones. Just a short list of examples:

    - Imperial Pint (568ml)
    - Liquid Pint (473ml)
    - Dry Pint (551ml)
    - Indian Pint (330ml)
    - The Australian pint (570ml)
    - The South Australian pint (425ml)

Source: https://en.wikipedia.org/wiki/Pint#Other_pints

If I have to rely on context, locality and customs to have a chance to understand what a unit of volume actually means, then there may be some issues with the underlying system. One reason why the metric system was invented, and why today almost every country in the world officially uses it, was to solve exactly these problems of ambiguity.

When I say "liter", there is no ambiguity, it's always 1 cubic decimeter.

[Aloha]

US Customary Units (https://en.wikipedia.org/wiki/United_States_customary_units) is not the same as Imperial (https://en.wikipedia.org/wiki/Imperial_units)

For what its worth, our system was standardized in 1832, and has been bound to SI equivalents since 1895.

For a broader comparison of the differences - https://en.wikipedia.org/wiki/Comparison_of_the_imperial_and...

[usrbinbash]

> and has been bound to SI equivalents since 1895.

But then why not just switch to using them directly? Having arbitrary units of measurement, and then going on to define them in SI units anway, is like dividing the day into 17.5 "Foobars", each of which consists of 4200 "Baz", and then defining that 1 Baz == 1.1755102040816328 seconds.

If there was some tangible advantage to doing that, I wouldn't say anything, but there isn't. Sure, 1 inch is roughly something-with-thumb-idk, only it isn't really, because everyone has different fingers, feet, arms, etc., so the entire "advantage" of having a real world comparison is out the window anyway.

[mulmen]

> But then why not just switch to using them directly?

Where it matters we already did. There's really nothing to see here.

[mulmen]

> It's not a question whether they are arbitrary, it's a question if they are technically consistent within themselves.

It's important to note that the US does not and has never used the "Imperial System" which didn't even exist before 1826 which is post-revolutionary war. US Customary units evolved around the same time as the Metric system and used names from the Dutch and English systems for historical reasons. The motivation being global compatibility, not internal consistency. The US was an original signatory of the treaty of the Meter. The British Empire (and thus, Canada) was not.

Personally I think internal consistency is overrated. It's nice to have but really reads like marketing wank. What matters to people doing work is if they can do their jobs. In those contexts change is far more costly than conversion to a new system. Tooling will already be built to deal with appropriate units.

One example of this is in metalworking machines. Those tend to last for decades and entire companies have built portfolios of designs and programs in thousandths (base 10 for those playing along at home) of an inch. It is unlikely that converting all those designs to microns would justify the cost, so we don't.

Almost all food packaging in the US has both systems printed on it but I am unclear how my dinner will taste better if I measure the ingredients in SI units. It just doesn't matter in that context.

[usrbinbash]

> The motivation being global compatibility, not internal consistency.

All the more reason to officially switch to metric. Because as of right now, only 3 countries in the world (US, Liberia and Myanmar) officially use imperial units, while the rest of the world uses the metric system.

> The US was an original signatory of the treaty of the Meter.

So? If I have a gymcard and don't go to the gym, it's not doing me any good.

> It's nice to have but really reads like marketing wank. What matters to people doing work is if they can do their jobs.

Indeed it does. That's why science and engineering are using the metric system. Including NASA btw. Being able to convert measurements easily, and have them correlate with our most common, radix 10, numerical system, is not "marketing wank", it's a built-in advantage.

If I want to figure out what mass of water falls on an area in the metric system, I can do the calculation in my head. If I have to figure out hundredweights per acre, given that X inches of rain fell, I'm gonna need a calculator, a conversion table, and social context to know which kind of "hundredweight" I'm supposed to use.

Oh btw. people "do work" in all these other countries. And guess how they measure things when doing that? Exactly: In meters and kilograms.

[mulmen]

> Because as of right now, only 3 countries in the world (US, Liberia and Myanmar) officially use imperial units

This is not true. The US has never used the Imperial system, we use the US Customary system, which has been based on the metric system since 1893.

> If I have to figure out hundredweights per acre, given that X inches of rain fell, I'm gonna need a calculator, a conversion table, and social context to know which kind of "hundredweight" I'm supposed to use.

Nobody is doing this.

> and social context to know which kind of "hundredweight" I'm supposed to use.

Since as you say everyone else uses the Metric system it should be pretty easy to figure out. As an American I have never even heard of a hundredweight, not sure why you are so fixated on this unit.

[usrbinbash]

> This is not true. The US has never used the Imperial system, we use the US Customary system

So how is using yet another different system defining arbitrary measurements that cannot be easily converted, do not directly correspond with the radix 10 numerical system, and are also not widely used make things better?

> Nobody is doing this.

Yes, people are doing such calculations all the time. How many concrete transports will a construction company need to make a foundation, if the depth is 2.2 m², the size is 97.2 m² and the specific weigth is 2.5 tons per m³?

How much rain did fall on Hamburg in 2022 given a city size in square kilometers, and an average fall of cm/day.

What kind of energy output can a solar farm provide given a conversion rate, panel efficiency, panel angle, and land size? Easy to do if all is in SI.

> As an American I have never even heard of a hundredweight

It's an official unit of the us customary system:

https://en.wikipedia.org/wiki/Hundredweight

[mulmen]

> So how is using yet another different system defining arbitrary measurements that cannot be easily converted, do not directly correspond with the radix 10 numerical system, and are also not widely used make things better?

For the same reason the metric (literally international standard) system was created. There were many similar systems in use. US Customary was a standard system for the whole country. The problem being solved was different standards for the units. US Customary solves that problem. Only the standard definition of the unit changed. This has been done within the metric system as well, even very recently.

> > Nobody is doing this.

> Yes, people are doing such calculations all the time.

What I mean is that specific conversion with hundredweights.

I’m unclear why anyone would do any of your example calculations in their head. They’re all so important that it would be done precisely on paper or electronically. All a worker pouring a foundation meeds to know is the desired dimensions. All the truck driver needs to know is the quantity ordered. Nobody is actually converting precise quantities of concrete or solar panels in their heads.

[Aloha]

Not to mention, you can do those calculations in your head if you're familiar enough with the subject matter, concrete guys do it all the time.

[Aloha]

Yes hundredweight is an official measurement, but it's not a widely used one (I think it might be used in the sale of nails only?) - which is the parents point. We'd just calculate it in pounds or fractional tons.

You act as if these calculations are simply impossible in customary units, they're not and we do them all the time.

To go on from this, we've converted everything that meaningfully effects our external competitiveness, as I said in a parallel comment I dont think our competitiveness would be helped or harmed if meat was sold in kilograms vs lbs or if we have temperature on the weather forecast in Celsius.

[saalweachter]

Hundredweight show up in agricultural settings -- you'll see the price of pork being $123/hundredweight, instead of $1.23/lb. I assume this is because the price of meats used to be pennies per pound, and people wanted the numbers to be bigger, $12.50/hundredweight instead of $0.125/lb.

[usrbinbash]

> You act as if these calculations are simply impossible in customary units, they're not and we do them all the time.

No I don't. I said they are more difficult than they have to be, and for no good reason.

> I dont think our competitiveness would be helped or harmed if meat was sold in kilograms vs lbs

https://gizmodo.com/five-massive-screw-ups-that-wouldnt-have...

Maybe not, but it would probably have helped in not having a 125 million dollar space probe go up in flames.

[saalweachter]

> How much rain did fall on Hamburg in 2022 given a city size in square kilometers, and an average fall of cm/day.

Oh, now you're in US customary unit territory.

Let me introduce you to the acre-foot.

The acre-foot is the unit of measure for reservoirs. For instance, the Ashokan reservoir is 8300 acres with an average depth of 46 feet. Its volume is 381,800 acre-feet.

If an area 10,000 acres received 3 inches of rain, you need 2500 acre-feet of reservoir to put the outflow in.

How big do you need to make your 2500 acre-foot reservoir? Well, if you're working with 100 acres, you make it 25 feet deep.

[johnwalkr]

Machinists have no problem working with designs in SI units on an inch-based machine. Lots of American companies use metric in designs and machine shops have to deal with it, although shops are moving to metric more and more. When they do this they keep and use their old machines with no problem although it’s an annoyance. Conversely metric machine shops can make inch-sized parts with no problems. Lots of material stock is inch-sized in the US, so even when you design in metric you have to consider this. But over time there is more metric stock available in the US, and for things like precision shafts there’s no cost difference anymore.

Regardless of everyday usage, in mechanical engineering/metalworking, the switch to metric has already been happening slowly since the 70s. Old machines and designs can stay in inches but most industries are already moving to metric unless there’s a compelling reason not to. You can see in Canada what things have stayed in inches because of regulations and material availability. House framing and steel weldments come to mind.