General > General Technical Chat
why is the US not Metric
CatalinaWOW:
All of these references to obscure units that are not widely used anywhere are a reminder that the traditional units did evolve organically, and were chosen for practical reasons. Either they were a convenient size for the job at hand or were based on a fairly universal standard. While the accuracy of a forearm length for a cubit, a foot length for a foot, or a thumb width for an inch are laughable now at one time they were the transfer standards of the world and met the need.
We have moved beyond that, transfer standards can be compared worldwide and are chosen largely without reference to convenience. The meter being nominally a specific ratio to the earths diameter is of almost zero practical significance, although the meter is a convenient length for measuring many things. The Farad is the best example of this. For most of my career as an engineer the Farad was a unit that had no relevance to real capacitors, and to this day the capacitors which can be measured in Farads are a tiny, tiny fraction of the total usage.
The unfortunate thing about the metric system relative to the organically developed units is that the available units are separated by orders of magnitude. For some things intermediate sizes would be convenient. Not necessary, just convenient. Just as having things related by orders of magnitude is convenient. Not necessary, but convenient.
The weird units like furlongs, bushels and others survive because in their application area they are, or were convenient. Things like bushels were appropriate when farms were small and human powered because that is about what someone can carry. Tons in any of their flavors just aren't convenient in that world. As industrial farming has taken over tons are probably a good convenient unit and bushels will disappear. Horse racing as a whole is impractical, it is an affectation in today's society. I see nothing that would drive it away from furlongs.
From a perfection standpoint we probably should abandon the current decimal metric system and define a new one with an octal base or hexadecimal base. That would eliminate all of the errors which result from approximating our decimal numbers with binary in our computers. You could keep the base units if it is too much trouble for those currently using metric to change. If you chose octal you could still teach kids to count using only the fingers - eliminating those interlopers the thumbs. Or you could show them how to count to thirty two using only one hand if you stuck to binary.
KL27x:
--- Quote ---Or you could show them how to count to thirty two using only one hand if you stuck to binary.
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No, officer. I was just expressing "4" in binary.
Zero999:
--- Quote from: TimFox on November 09, 2019, 03:23:29 pm ---"Yes, imperial and customary are a nightmare, because they use different bases, even within the same scale: 12 inches in a foot, 3 feet in a yard and 1790 yards in a mile."
Reply: the US statute mile is 8 furlongs of 220 yards each, or 1760 yards.
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Whoops, typo corrected.
--- Quote from: KL27x on November 09, 2019, 07:03:22 pm ---
--- Quote --- I recall getting one question wrong because I had to convert from PSI to lbf/ft^2.
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You need to think again, because imperial was not the issue. Unless your mistake was not knowing there are 12 inches in a foot (haha no), you could have made the same kind of mistake converting kg/cm^2 to kg/m^2. "Oh, there are 100 cm in a meter, so it's a 100:1 ratio; we move the decimal point 2 spots to da right..."
(And in real life we don't get to look at the multiple choice answers to see which one matches our numbers but with the decimal point off by a couple places and choose that one.)
--- Quote --- I think after that I started to convert all US Customary Units immediately to Metric MKS (Metre, Kilogram, Second). Do the maths, then I know I was guaranteed a MSK final result (like Pa/Pascal, N/Newton, J/Joule, W/Watt, etc.) then use the conversion tables to convert what ever the question asked.
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You could leave them in w/e units they start in. If they are in imperial, leave them in imperial. But convert all the distance stuff to a single unit. I.e., if your data includes inches and cubits and HarryPotters, convert everything into inches. You are converting all that stuff AND the inches to metric and then back into imperial, for no reason. You could save some conversions, at least.
You are this stuck to metric that THIS makes sense to you to do this unnecessary calculation. They're just units man. In the reverse scenario, I have no loyalty to imperial. They could be Papasmurfs/PappaJohns ^3, and I'll do the calculations in those units. I'm not going to convert into imperial then back to w/e.
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What makes customary/imperial much more difficult than metric is not so much 12 inches in a foot, 3 feet in a yard, 1760 yards in a mile etc. but derived units. The metric system links everything with nice powers of 10. Granted, it's still possible to make mistakes involving the decimal place, but it's much easier to move from linear distances, to area and volume. For example, a litre is 1000cm3, a nice multiple of ten, an imperial pint (20floz) is 34.677in3. This is why it's often much easier just to convert everything to metric, perform the long calculation and convert it back to imperial/customary again.
KL27x:
^True, and good point.
Tepe:
--- Quote from: CatalinaWOW on November 09, 2019, 07:18:37 pm ---The meter being nominally a specific ratio to the earths diameter is of almost zero practical significance
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It is of no significance, practical or otherwise, because that's not the definition of the meter.
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