Question Why Whateley Science isn't done right.

There's a simple answer to this (ignoring the lack of scientific method in a lot of scientists featured in the universe):

The.

Fucking,

Imperial.

System.

Simply put, the use of the Imperial Measurement System by the Powers Lab teachers, the Science Teachers, the various scientists throughout the stories (including, but not limited to Dr. Emil Hammond) is completely wrong. Despite this being set primarily in America- a land seemingly obsessed with keeping a inaccurate and flawed system of meaurement- the world scientific standard is the Metric System. No self-respecting (or otherwise) scientist, engineer or programmer would willingly use that system for standard measurements. Cases in point:

Ayla and the New School wrote: was pretty sore by the time I got to Powers Lab. Mrs. Bohn had most of the class doing weight-lifting, which I really didn’t feel like doing. Some student aides who knew what they were doing were spotting us and making sure that we lifted properly. Apparently, I didn’t know squat about lifting the correct way. Pardon the pun.

At my heaviest, I lifted 3847 pounds, then 3795 pounds, and finally 3871 pounds. Man, I needed a break between martial arts and this stuff.

Mrs. Bohn looked at my results and said, “That’s normal variation, dear. So you have a mean of…”

“3841 pounds,” I supplied.

“…and a standard deviation of…”

“39.06 pounds,” I said.

She pursed her lips, “But you don’t have that many significant digits dear.”

“Okay, 39 pounds, rounding off.”

She nodded, “Much better. Now a coefficient of variation around 1% is quite good.”

...Which is unusual for a science class- TMK (as I'm Australian) the US uses the metric system for science classes and the imperial system for everything else. Even IF it is a thematic science class.

Ayla and the Late Trevor Goodkind wrote: Dr. Hammond walked in front of me and smiled. It was the kind of smile you see on Tom’s face when he has Jerry helplessly trapped in a corner. He said, “You’re showing some interesting abilities. But I think you can improve with time. I believe that I can help with that.”

A shudder ran through me. Oh God, he couldn’t mean what I thought he meant!

He nodded to his assistant, and the guy bent over a control panel. Suddenly the confinement spheres began to hum. They began to vibrate. And then they began to move away from each other.

I screamed in agony as the spheres began pulling me apart. I tried as hard as I could to go heavy, and in a matter of seconds I could feel the change inside me.

I began to sink lower. I began to feel like I was strong enough to resist the pull of these freaky gadgets. I pulled as hard as I could, and managed to bend my arms enough to pull the spheres several inches toward my head.

The assistant said, “You were right, sir. Its weight has jumped to 1130 pounds, and its strength has just moved up to Level Three.”

“Good. Increase the strain.”

Oh crap! He wouldn’t!

Oh, who was I kidding? This was Emil Hammond. Of course he would.

The strain on my arms and legs increased, until it was pulling me apart again. I concentrated as hard as I could, but the pull was slowly overcoming my best efforts.

“Weight up to 1260. Strength nearly at Level Four.”

I focused as hard as I could, but the pain in my limbs was agonizing. I was really afraid they were going to let me be ripped to pieces.

I was talking to myself by then. “Come on, Trev! Concentrate! Try harder! Don’t let this bastard win!”

“Weight at 1340 pounds. Strength solidly at Level Four.”

And then the pull of the spheres overwhelmed me, and I screamed at the searing pain.

...which is even weirder because this is a professional scientist conducting experiments, and even IF he's a immoral asswipe, he SHOULD be using the metric system for measurements. If he wasn't, he'd be the laughing stock of the scientific community. All scientists, regardless of nationality or country of residence, use the Metric System for experimental measurements.

However, Dr. Quintain seems to flip-flop a bit, as evidenced by his talk about physics with Lily in The Play's the Thing:

The Play's the Thing wrote: ...well it was about four or five minutes later that the Sim ended, sir.”

He rocked back and forth on his heels like I’d just told him the cure for cancer. “Extraordinary!” he repeated again. “In any event, Miss Turner, this is the equation you’ll need. KE = .5(m)(v2) where KE is Kinetic Energy in Joules, M is Mass in kilograms and V is the velocity of the projectile.”

where Quintain uses the metric system for calculating kinetic energy (although technically he should have given her the calculation for Delta KE (Change in Kinetic Energy) as that would be more appropriate if time was a variable in the overall calculations. If I'm wrong, correct me. I'm still a little out-of-it due to a incident I'll post about on The Quad later).

So, comment and discuss I guess???

CrazyMinh wrote: ...which is even weirder because this is a professional scientist conducting experiments, and even IF he's a immoral asswipe, he SHOULD be using the metric system for measurements. If he wasn't, he'd be the laughing stock of the scientific community. All scientists, regardless of nationality or country of residence, use the Metric System for experimental measurements.

That's not true. Numerous measurements are carried out in SI units, but not all.

CrazyMinh wrote: No self-respecting (or otherwise) scientist, engineer or programmer would willingly use that system for standard measurements.

You'd be surprised... no, shocked and horrified, how wrong you are about this. I know it always bothers me whenever someone put forth as a scientific expert here uses the US system, and I have lived my entire life here.

(Note that the US system is not the Imperial system, being loosely based on the even older Winchester system, which differs significantly from the British Imperial system. But that's a side note.)

And no, most high school classes here don't use metric. If anything, from what I have seen, use of metric has been almost discontinued in basic science classes, due to push-back against it from parents and political leadership. College level and college-prep courses almost always do use metric, true, but most people in the US don't take any science courses after their first year of high school (year nine of twelve, for those who are unfamiliar with US education) - and they go out of their way to forget it as soon as possible, because science is Fake News to most Americans today (always sort of was, really, except right after Sputnik).

(Technology is another matter entirely, but then, most of My Fellow Merkins can't tell one from the other, anyway.)

Much like the Roman Republic, the US is at its best when it is ruthlessly pragmatic, and at its worst when it is mindlessly dogmatic, neither of which really contribute to an interest in science for its own sake. The fact that so many Americans do end up falling into the sciences is less from any cultivation than from what amounts to benign neglect - broadly speaking, students aren't particularly encouraged or discouraged to it (or any other specific field), but it is a good escape from an often vicious culture (not that this is unique to the US in any way...) and there's a decent living to be made from it for those who take the trouble to do so on their own.

It may seem dysfunctional, but it does mean that those who do go into a given field as a rule really care about getting good at it - in its own way, it works. But it does mean that things like the US weights and measures don't get challenged often in general life.

Indeed, the place where metric is used by Americans the most is the military, and that came about mainly because of the expectation of having to fight a land war in West Germany, and the practicalities of the NATO alliance in general.

JG wrote: I use the metric system mostly out of habit because military.

YEP!
5.56mm
9mm
20mm
and so on!

but lets not even mention 'gauges' whole new load of apples there!

In all honesty, it just means many of us here in the US have memorized the easier of the conversions.

2.54 cm to the inch
1.6 km to the mile
2.2 pounds to the kilogram
30 ml to the fluid ounce
1 cup is close enough to 235 ml
1 quart is very nearly 1 liter

We just get used to it. We can bake with volumes, we can bake with weights and ratios.

The only difficult conversion is temperature. It's hard to perform the conversion between Fahrenheit and Celsius in your head.

You should really be confused by the British! Fluids in pints (except when it is ml), a person's height in meters, but their weight in stone, long distances in km (or miles, depends on who you ask), speeds in kph, etc.

Take it back to Whateley, and the majority of the student body can do the mental math and get an accurate conversion regardless of what units they're told.

There is nothing inaccurate about the system of measurements that is used in America. You only get bad data from bad measuring.

The foot is actually a better unit of measure than the meter, because I can easily divide the foot by 2, 3, 4, and 6. 8, and 9 also give nice fractions. Using the base 10 metric system means only 2 and 5 divide nicely.

Valentine wrote: There is nothing inaccurate about the system of measurements that is used in America. You only get bad data from bad measuring.

Not keeping track of the precision and accuracy (and bias) of the methods used can also cause problems.

FWIW, I attended public high school in Georgia from 2002-2006, and all three science classes I took used metric. Those were the advanced-level versions of the classes, though; I have no idea whether the general-levels followed suit. It never even occurred to me that anyone would use anything other than metric in a science class. But regardless of what goes on in general-level classes, I would expect a high-end school like Whateley Academy to use metric in scientific contexts.

That said, calling Powers Theory and Powers Lab a scientific context might be a bit of a stretch. They're billed as science classes, but in a lot of ways they're more like mutant-oriented Health and PE classes.

As for Dr. Hammond, he's evil, so of course he's using obnoxious units.

Kettlekorn wrote: FWIW, I attended public high school in Georgia from 2002-2006, and all three science classes I took used metric. Those were the advanced-level versions of the classes, though; I have no idea whether the general-levels followed suit. It never even occurred to me that anyone would use anything other than metric in a science class. But regardless of what goes on in general-level classes, I would expect a high-end school like Whateley Academy to use metric in scientific contexts.

In the US, where the school is located, the weights for casual weight-lifting are usually provided in increments measured in pounds. Collecting all the maximum deadlift and bench press data in pounds ensures the measurements would be in consistent units - something that matters more to the bookkeeping than the system of units used.

Kettlekorn wrote: That said, calling Powers Theory and Powers Lab a scientific context might be a bit of a stretch. They're billed as science classes, but in a lot of ways they're more like mutant-oriented Health and PE classes.

The wiki lists "Basic Powers Management" as a Phys. Ed. course, just as well for the kids who aren't turned into de facto jocks by their manifestation. (NH, IRL, requires 1 credit, [i.e., 2 semesters] of Physical Education and 1/2 credit of Health Education)

null0trooper wrote:

Valentine wrote: There is nothing inaccurate about the system of measurements that is used in America. You only get bad data from bad measuring.

Not keeping track of the precision and accuracy (and bias) of the methods used can also cause problems.

Correct me if I'm wrong, but doesn't US manufacturing use hundredths and thousandths of inches when precision is required?

Valentine is right though about easy division and trigonometry using US customary units. Watching a home contractor work is truly a wonder when it dawns on your how fast they're doing math in their head.

Katssun wrote:

null0trooper wrote:

Valentine wrote: There is nothing inaccurate about the system of measurements that is used in America. You only get bad data from bad measuring.

Not keeping track of the precision and accuracy (and bias) of the methods used can also cause problems.

Correct me if I'm wrong, but doesn't US manufacturing use hundredths and thousandths of inches when precision is required?

That likely depends on what's being made, but you'll see some oddball figures from trying to represent 1/8", 1/16", 1/32", and so forth in base-10.

Katssun wrote: Valentine is right though about easy division and trigonometry using US customary units. Watching a home contractor work is truly a wonder when it dawns on your how fast they're doing math in their head.

Especially when you consider that with dimensional lumber, a two-by-four isn't two inches by four inches, but 2 of them glued together still comes out the size of a four-by-four.

The only times I use imperial are for:

- D&D

-Warhammer 40k

- Shadowrun

- Really any tabletop game that uses those measurements.

The problem with the imperial system is that...well, take a look at a ruler with imperial measurements. For one, it's not base-10, so thats one issue. Two, the gaps between the inch markers are a lot larger than those between millimetres. This makes it kinda inaccurate when it comes to precise scientific measurements. Also, since most of the scientific community uses the metric system, using it for science means skipping the awkward conversions between measurements.

Also, while it IS easier to divide, and while Americans may be comfortable with it, I guess that's a thing coming from upbringing rather than actual ease. I find the metric system easier, so I guess it's whatever system you're used to. Either way is technically right, it's just most of the world uses metric for daily life.

It occurred to me to post a link to an earlier post of mine explaining a bit about US primary and secondary education , for the sake of those who may be unfamiliar with the oddities of the American education sy... er... whatever it is.

CrazyMinh wrote: The problem with the imperial system is that...well, take a look at a ruler with imperial measurements. For one, it's not base-10, so thats one issue.

I find it troubling that an engineer typed this on a 64-bit machine that emulates base-10 mathematics without ever having seen an engineer's scale nor, even after not-reading the above posts, realizing that the beat-up wooden ruler he was looking at as an example of a scientific tool for measurements was ruled for carpentry.

Minh, there are steel tapes (and sounding tapes) ruled in hundredths of a foot. Yes, that's a longer unit of measurement than a mm. No, that doesn't make mm a better unit of measurement. If that makes no sense to you, it's because you don't understand the science and mathematics behind scientific observation.

CrazyMinh wrote: Two, the gaps between the inch markers are a lot larger than those between millimetres. This makes it kinda inaccurate when it comes to precise scientific measurements.

Most people would use a micrometer for making small, precise engineering measurements, not a carpenter's rule, not a seamstress' tape.

CrazyMinh wrote: Also, since most of the scientific community uses the metric system, using it for science means skipping the awkward conversions between measurements.

This is the kind of willful ignorance about observations and measurements that leads to broken equipment. Someone thought they could get away with just shifting a decimal point and everything would be all right.

It can get people killed when some knucklehead thinks "millimole, milliequivalent: same thing"

1/16ths of inches are fairly common on most rulers, tape measures, and so on, and they're 1.5 millimeters. Precision isn't a big issue for US Customary. As null0 pointed out, that's what micrometers and calipers are for.

Vernier scales are what make no sense at all to me. Thank goodness for dial and digital calipers.

The common case that the metric system is scientific and not based on arbitrary things goes out the window when you look at it more carefully. Both systems are silly and arbitrary.

- THE Kilogram was at last and finally removed. One lump of metal. The pound was standardized for trade long, long ago, and isn't much different.
- Celsius is the temperature water freezes and the temperature it boils for 0 to 100. Fahrenheit (aside from being harder to spell) is the lowest temperature he could get water to without it freezing (equal parts of ice, water and a salt), and about the temperature of the human body. Both equally as easy to calibrate.
- We both use seconds. Time matches nothing. 60s -> 60 min -> 24 hours -> 365 days -> 1 year...ish. How very base 10.
- Alcohol is still measured in Imperial units, even if the milliliters come out to a number divisible by five.
- The standard industrial barrel is 55 gallons. No one buys 208.2 L barrels.

null0trooper wrote:

CrazyMinh wrote: The problem with the imperial system is that...well, take a look at a ruler with imperial measurements. For one, it's not base-10, so thats one issue.

I find it troubling that an engineer typed this on a 64-bit machine that emulates base-10 mathematics without ever having seen an engineer's scale nor, even after not-reading the above posts, realizing that the beat-up wooden ruler he was looking at as an example of a scientific tool for measurements was ruled for carpentry.

Minh, there are steel tapes (and sounding tapes) ruled in hundredths of a foot. Yes, that's a longer unit of measurement than a mm. No, that doesn't make mm a better unit of measurement. If that makes no sense to you, it's because you don't understand the science and mathematics behind scientific observation.

CrazyMinh wrote: Two, the gaps between the inch markers are a lot larger than those between millimetres. This makes it kinda inaccurate when it comes to precise scientific measurements.

Most people would use a micrometer for making small, precise engineering measurements, not a carpenter's rule, not a seamstress' tape.

CrazyMinh wrote: Also, since most of the scientific community uses the metric system, using it for science means skipping the awkward conversions between measurements.

This is the kind of willful ignorance about observations and measurements that leads to broken equipment. Someone thought they could get away with just shifting a decimal point and everything would be all right.

It can get people killed when some knucklehead thinks "millimole, milliequivalent: same thing"

\



Well fuck I just realised what I typed. Also fully realised what I was responding to so here's a revised message.

I've...never actually seen imperial measurements on our equipment. At least,. I don't recall ever seeing equipment at uni with imperial measurements. If so, I didn't really notice.

In addition, yes, a micrometer is better for precise measurements, and a ruler or other device would only be used if you were either desperate or inept. Or possibly both. Yes, I'm aware that metric/imperial conversions are pretty easy. I just can't do them in my head because I work primarily and mainly with metric. I don't even KNOW the standard conversion between cm and inches off the top of my head. Yes, I probably should know this, but in the engineering course I've been doing it's never come up to my knowledge. That, or my memory is faulty as to the coursework I've done over the past five or so years,

Also, sorry for posting the last post, I was in a bit of a haze, and I completely missed the fact that I justified my statements with the use of distance between points on a ruler. That was stupid.

and that was in italics

The cool thing about US customary units is that when we make a formatting error while writing about them online, we can click on the "Action" button and select the "Edit" entry to correct the post instead of just throwing our hands in the air like the metric world.

Katssun wrote: You should really be confused by the British! Fluids in pints (except when it is ml), a person's height in meters, but their weight in stone, long distances in km (or miles, depends on who you ask), speeds in kph, etc.
.

For those interested, speaking as someone who grew up in the south and now lives in the north.


In regards to which is better for what: It depends on the person and their own comfort level. Whether you can divide it easily or not becomes pointless, because Imperial is easier for certain things, Metric is better for others.

And clearly, the better system will be the new SI Base Units after their 2019 redefinition.....

So, Standard vs Metric. I use both. High school science was almost entirely standard. The Navy used both... Depth in fathoms and feet, range in meters, pressure in PSIA/PSIG/PSID, weight in pounds and metric... You get the idea. It made firing solutions sort of fun, you had to work with both systems. Then I went and got a BS degree. Both systems were again used. So I am going to say that both are acceptable.

As for accuracy. The metric system uses decimals which inherently make it less precise. Fractional systems are actually more accurate for most measurements. The closest a decimal system can get to 1/3 is 0.66..., which is close, but not exact. The fractional system however can pin down any value exactly (provided you are willing to write out a large/long enough denominator). adly, some years ago it was decided to retroactively apply metric values to the definitions of many standard units. That was a mistake as the basis for metric measurements is based on an artifact that was defined as "1 kilogram"...so even if it was ever damages, worn down or otherwise altered, it would still be considered "1 kilogram" even though the actual mass had changed. That issue has already been observed in the divergence between the IPK and the official standard copies provided to various nations.

Interestingly, because of the redefinition of standard units according to metric units, the standard system is at least as accurate as metric, yet, because the standard system evolved from practical applications instead of mere arbitrary determinations, it applies to a larger range of applications and can exist independently of the metric system and even independently of any other system or artifact. The metric system however depends upon artifacts that have been proven to change over time, rendering it imprecise and less functional by the very basis on which it was founded. Which is why the value of the kilogram is being redefined even now in terms of the Planck constant. As I recall, the value of the meter has already been redefined. Systems based on arbitrary values chosen in isolation from practical application have consistently suffered from the need to be redefined over and over again. Meanwhile, those based on actual fixed and observable values or based on practical application are able to withstand the ravages of time far better.

Also, one more thing...there are 10 types of people in this world, those that understand binary and those that do not.

This would be a bad time to say that I dislike both, wouldn't it? But then, I favor using a base-16 numeric system over decimal or duodecimal anything, and would want a system based on a natural unit system such as reduced Planck units or Lorenz-Heaviside units, given in powers of 2, including for time.

Not gonna happen, though. For human-scale use, anything based directly on a natural unit system would probably be extremely problematic, even if the 'effective base units' were in extremely large powers of two or 16.

And yes, I am aware that (with the change in the definition of the kilogram this year) metric measurements are technically defined from natural units, but that 'basis' is a forced fit to try and make the new definitions consistent with both modern physics and the older definitions.

I should also add that, AFAICT, the NBS currently defines the US customary units solely in terms of their metric conversions. Historically, the US government was originally going to use metric, based on Jefferson's recommendation, but then the XYZ Affair and the Napoleonic Wars put a damper on the American enthusiasm for all things French. Since Congress basically ignored the issue of weights and measures (despite that being a Constitutionally-mandated responsibility), each state was left to it's own devices, and for a long time, it really was simply 'customary' measures without a formal standard.

When Congress did enact a standard 1866, it chose metric - but it was only applied to the assessment of tariffs. It wasn't until, uhm, the 1890s I think, that the National Board of Weights and Measures was established, and since they didn't want to rock the boat, they basically said, 'sure, keep what you're doing, we'll just make a standard version of that'. So US customary units are mostly a product of benign (or not so benign) neglect.

MM2ss wrote: The fractional system however can pin down any value exactly (provided you are willing to write out a large/long enough denominator).

Not quite. Irrational numbers cannot be represented by fractions. Of course, that means they can't be represented by decimals either since decimals are just an alternative representation of a particular class of fractions.

Anyway, there is absolutely nothing stopping you from using fractions in metric. The metric system just doesn't waste everybody's time assigning custom labels to a bunch of weird and random fractions. It uses predictable labels at convenient powers of ten, but nobody is forcing anyone to talk about 3.333 mm instead of 1/3 cm.

MM2ss wrote: As for accuracy. The metric system uses decimals which inherently make it less precise. Fractional systems are actually more accurate for most measurements. The closest a decimal system can get to 1/3 is 0.66..., which is close, but not exact. The fractional system however can pin down any value exactly (provided you are willing to write out a large/long enough denominator).

What a load of hogwash!
First, no fraction is "inherently more precise" than another. Precision depends on the equipment you are using, not on the numbering system.
And yes, duodecimal gives you nicer fractions if you are trying to divide in thirds... but not if you are trying to divide in fifths. Fourths? Just go one submultiple down. And none of them is good for dividing in sevenths. And, as Kettlekorn pointed out, if it's important enough for the application, there's nothing stopping you from making a ruler with different divisions.

MM2ss wrote: Sadly, some years ago it was decided to retroactively apply metric values to the definitions of many standard units. That was a mistake as the basis for metric measurements is based on an artifact that was defined as "1 kilogram"...so even if it was ever damages, worn down or otherwise altered, it would still be considered "1 kilogram" even though the actual mass had changed. That issue has already been observed in the divergence between the IPK and the official standard copies provided to various nations.

The Imperial/U.S. Customary units had THEIR OWN reference "pound" and "inch". Part of the reason for the change to a metric-based definition was that, well, their reference objects were really crappy in comparison. You mention the very small variations on the IPK? Those standards had variations several orders of magnitude larger -- between two consecutive measurements made in the same room, in the same day. Instead of redoing all the work the Bureau of Poids et Measures had already done, they simply adopted the SI units as reference.

Interesting anedocte: the reason why there is no longer an "American inch" and a "British inch" (as there are a number of units in the Imperial/US Customary systems) is due to a Swedish inventor. Brits defined the inch as 25.399977mm measured at 62°F, while the US defined the inch as 25.4000508mm measured at 68°F -- both definitions having been set before there were reliable methods to check them (the US inch was defined in this way by law back in 1866). Carl Johansson, the Swedish company that invented, patented and supplied both countries with gage blocks (an essential tool to do precision measurements) had been supplying both countries with gage blocks in which was the inch precisely 25.4mm... and nobody noticed for years because, well, they didn't have anything better than the Johansson gage blocks to check their quality. Eventually both the UK and the US changed their definitions to the one Johansson used. Check, for instance, this reference (PDF) (a publication by Mitutoyo)

MM2ss wrote: Interestingly, because of the redefinition of standard units according to metric units, the standard system is at least as accurate as metric, yet, because the standard system evolved from practical applications instead of mere arbitrary determinations, it applies to a larger range of applications and can exist independently of the metric system and even independently of any other system or artifact. The metric system however depends upon artifacts that have been proven to change over time, rendering it imprecise and less functional by the very basis on which it was founded. Which is why the value of the kilogram is being redefined even now in terms of the Planck constant. As I recall, the value of the meter has already been redefined. Systems based on arbitrary values chosen in isolation from practical application have consistently suffered from the need to be redefined over and over again. Meanwhile, those based on actual fixed and observable values or based on practical application are able to withstand the ravages of time far better.

OK, this is not a load of hogwash. It's a supertanker of hogwash. Perhaps an entire Caspian Sea of hogwash. "Customary standards can exist independently from any other system or artifact..." Yes, customary systems evolved from practical needs. But they were ridiculously ill-defined. Back before standardization, a pound could vary as much as 100% from one town to another. Inches? Feet? Don't get me started on those. There were probably more different sizes of "feet" back before standardization than actual feet in living people. They weren't any sort of consistent measuring system; they were an invitation for trouble. Going to buy a pound of wheat? Sure, a pound... but will the shopkeeper give you a pound by your estimation or by his estimation? Remember, one might be as little as half of the other. The reason why the metric system kept being used by the countries invaded by France even after the fall of Napoleon was because nobody wanted to go back to the mess that was before. England had a sort-of standardized foot and pound -- by having reference objects, not by any intrinsic "footness" of the foot or "poundness" of the pound.

Years and years ago, in drafting class which was a lab going with Statics of Materials (engineering), we were shown the value of having multiple scales for drafting. The '10' scale had an inch divided into 10 precise units. The '20' scale - same but 20 units. There were 6 scales per triangular-shaped 'scale - the decimal one had 10, 20, 30, 40, 50, and possibly 80 (I don't have them and haven't used them in decades). The 'inch' scale had various drawing scales, such as 1 inch = 1 foot, etc - and these were used mostly in architectural drawings. Again, haven't used them in decades. When we did some remodeling projects, I used a home-design CAD program which did all that nonsense for me.

It's like anything - you can always find something you can't divide your units evenly by.

I did QA for a USA manufacturer for about 2-3 years. I made measurements in both inches and millimeters depending on the design of the object I was measuring. All my weights were done in grams, yet all the material I used in my process was sold in pounds... I used either 1000 lb or 1500 lb boxes of raw materials to start with. Anyway, for my measurements I used either a digital caliper (I bought my own 12'' caliper) or a vernier scale caliper. I could easily get measurements that were accurate to 0.001+- 0.0005. (oh these were measurements in inches...) Most of the tolerances I had to work with were +-.005. So I had to be careful especially with the vernier caliper as it was very easy to misread it... But the truth is that so long as you have a good definition of your base unit any unit of measure will do fine. I've used a tape that was marked in 10ths of a foot for surveying, not often enough to be more than a tyro at it, but enough to know that any unit can be divided any way you want. The main thing is that you start with a definition that you don't change very often and that you use that definition across all aspects of your measurements.
Like a lot of people here I became much more familiar with the SI measurements due to using them in the military. But I would hesitate to say that either SI or ASE is better for science or engineering. Both have been used and work well where they are used, consistency in the set of measures you use is more important than the set of measures you use. And consistency is achieved by using very finely granular constants, however those constants are objectively set.

MM2ss wrote: Systems based on arbitrary values chosen in isolation from practical application have consistently suffered from the need to be redefined over and over again. Meanwhile, those based on actual fixed and observable values or based on practical application are able to withstand the ravages of time far better.

Which fixed and observable values are talking about? The whole point of the ongoing redefinition is to set the values to a group of universally observable - as in, they can be observed anywhere in the universe, regardless of relative motion - physical constants (or rather, from the normalized forms of those constants, where the value of the constants is always 'one' and everything else is scaled from that) which as far as we can tell have been fixed since the universe formed.

Now, as I said, I would prefer a model in which those constants had been the basis from the outset, but that, as I also said, ain't gonna happen.

As for 'based on practical application', Sir Lee has already disposed of this inanity. Yes, they were 'based' on human-scale elements of what used to be daily life, but they were defined differently in different places, because the 'human-scale elements' were themselves highly variable. A human pace? How tall is the person being measured from? The weight (not mass, note) of grain of wheat? Two grains from the same field in the same year may vary by as much as an order of magnitude. The weight of a stone? Good luck with that one. Over time, the 'customary units' in different locales invariably came to be based on unique artifacts, because that was the only thing 'invariable' that could be used.

And as Sir Lee points out, each village and each merchant had their own versions of those unique gauge objects, and it wasn't until the early 17th century that anyone even tried to impose a common value on any of them - generally by issuing a 'standard model' gauge item to each party that needed one. And as the video I linked to points out, standardization - not just of metric values but in general - would only be accepted if enforced by law.

For that matter, which 'human scale elements' were used differed from place to place and time to time . Can you tell what the value of a Mesopotamian cubit was based on (actually, you might, but it does illustrate the earlier point), and how it differed from a Macedonian cubit or an Egyptian Royal cubit? How do you define a sheckel-weight without a shekel? Can you tell me the definition of a rod? a furlong? Is a smoot (which admittedly is meant humorously) any less valid than an ell? Why do different US customary barrels differ based on the liquid (or in some cases, grain) being measured?

(BTW, in most of the world, US barrels were never used as a common measure for beer; they used a lot of different measures in the past, but today most places use liters, and 'barrels' isn't used, period).

Schol-R-LEA wrote: (BTW, in most of the world, US barrels were never used as a common measure for beer; they used a lot of different measures in the past, but today most places use liters, and 'barrels' isn't used, period).

No one said that US barrels were used to measure beer. Katssun's actual statement was:

- Alcohol is still measured in Imperial units, even if the milliliters come out to a number divisible by five.
- The standard industrial barrel is 55 gallons. No one buys 208.2 L barrels.

Yes, across the English-speaking world beer is still sold as pints, whiskey in fifths and barrels, and shots are mixed by the jigger or the ounce.

Katssun is also correct regarding the standard for shipping industrial liquids is chosen so that it all measures out evenly into what Americans call "drums", sometimes "barrels", depending on the use.

Btw, in the US grain is commonly measured in bushels, although I have purchased grain by the pound. If you go looking for a barrel of rye, expect to see a whole lot of whiskey being offered.

FWIW, I personally use a 5-gallon carboy for brewing with the expectation of needing 2 cases for bottling.

Brazil was (officially at least) an early adopter of the then-called metric system... but even though most stuff nowadays is done in metric here, there are a few things that stubbornly refuse to change:
- Paint is still sold by the gallon. Don't ask me why, it shouldn't be a big problem switching to liter-based sizes (paint thinner is sold by the liter, by the way). Worse, the country was already metric when industrially-made paint became a thing. I think it was mostly because American companies dominated the market early on.
- Screws: we have to deal with both American and metric sizes. Metric is slowly gaining ground (cars are mostly metric nowadays, for instance), but I expect that inch-sized wrenches will be a required part of every mechanic's toolkit for a long, long time.
- Tires. Thanks to early American domination of the car industry and the inherent difficulty in switching over, tire sizes are inch-based -- worldwide. The only chance for a switch to metric sizes is a radical change in technology, such as Michelin's Tweel or something similar finally catching on. And no, there wouldn't be any good reason to make such new wheels compatible with old wheel-and-tire systems; they behave quite differently, and require a different tuning of the suspension -- so, making it easy for your average idiot to fit them to existing cars would be a bad idea.
- Similarly, shipping containers were originally based on US customary units, so their standard dimensions are "rounder" when measured in feet than when measured in meters. And shipping is usually calculated in TEU, or "Twenty-foot Equivalent Unit", which is the size of the smallest standard container (a twenty-foot regular-height container). Changing the size to metric dimensions "just because" simply won't happen.
- But... the 55-gallon drum Katssun mentioned is actually more properly called a 200-liter drum . Yes, it tends to have a slightly higher capacity , and there is some dimensional variation from maker to maker... but they are filled to 200 liters.

Sir Lee wrote: - Tires. Thanks to early American domination of the car industry and the inherent difficulty in switching over, tire sizes are inch-based -- worldwide. The only chance for a switch to metric sizes is a radical change in technology, such as Michelin's Tweel or something similar finally catching on. And no, there wouldn't be any good reason to make such new wheels compatible with old wheel-and-tire systems; they behave quite differently, and require a different tuning of the suspension -- so, making it easy for your average idiot to fit them to existing cars would be a bad idea.

Oh, tires are much worse. They're measured in both systems!

P225/50R16 tires translates to: Passenger vehicle, 225mm cross section, 50 percent of the cross section measurement for the sidewall, radial tires, rim size of 16 inches.

My little hatchback goes through its fair share of winter and summer tires.

At the farm level in the US all grain is sold by weight. One bushel of wheat for sale is 60lb no matter the test weight.

Down here in warm South America, things like coffee and cereals are nominally priced by the "sack" -- which used to be an unit of volume, way back when they were actually packaged into sacks. Nowadays all the shipping is done in bulk and the "sack" is just an accounting unit, like "barrel" for crude oil. Depending on tradition (partly originating from the particular commodity's average density), a "sack" may be 40, 50 or 60kg.

Meat cattle is... odd. Cattle is sold to the slaughterhouse by the "arroba", which is a weight unit equivalent to 15kg. This is not the odd part; the odd part is that the cattle is weighted, a fudge factor is applied to estimate how much of the animal is meat, and then the result is divided into 15kg units. So, a steer weighing 450kg is *not* a 30-arroba steer.