6 ms·

>I would argue that being limited to a single unit system is like being limited to a single language. In principle, no one needs more than one but in practice t

by D_Alex 12y ago

>I would argue that being limited to a single unit system is like being limited to a single language. In principle, no one needs more than one but in practice the differences in expressiveness for different purposes are interesting and useful. After considerable reflection, I have come to the view that in fact the differences are not interesing and not useful. What is useful though is consistency and ease of application (which the metric system has) and familiarity (which just depends on the circumstances). I work in the oil and gas industry, and I had to learn to think in terms of bizarre units like stcf/bbl, or pounds per gallon. In the end, the only driver was that once you digest enough information, you can compare things on a like-for-like basis... if you know the horsepower ratings of 10 car models, it is more immediately useful to be given the horsepower of the car you consider buying rather than its power output in kW. But in the end I see no downsides, only upsides, if the entire industry switched to the metric system. stcf/bbl (standard cubic feet per barrel) by the way is a customary measure of the amount of gas dissolved in the oil. After 25 years in the industry, I know for example that 1000 stcf/bbl represents a gassy oil that will take some effort to stabilise, and 100 stcf/bbl is a relatively dead crude... so inormation about new crudes is useful to me in this form. But - what a weird unit it is! The information could much better be provided as a dimensionless ratio, eg gas-to-oil ratio of 200 for gassy oil would be intuitive and better suited to use in further calculations, and once you've seen enough data expressed in this way, the familiarity issue is taken care of. I invite you to provide counterexamples, where the customary unit has an inherent advantage (familiarity does not count). I can't think of any.

Mikhail_Edoshin 12y ago
Cooking units are much better suited for the task than metric units. Typographic units are non-metric and metric units are inconvenient in typography, because millimeters are too big for character sizes and too small for page units and centimeters are both too big and too small at the same time. French (?) shoe sizes are numbered like 38, 39, 40, 41, etc. and the difference between these sizes are 2/3 cm, because it's a practical difference to mass-produce different shoe sizes. It's not metric, obviously. Parsecs are not metric. Heck, light years are not metric; and look at how rich the unit is, it tells you a lot about the distance. Try to express the distance to Alpha Centauri in metric units and comprehend it.
- davty 12y ago
  1 light year = 9.4605284 × 10^15 meters
  - knodi123 12y ago
    heh, the numeric part is pretty much 3*Pi.
  - Mikhail_Edoshin 12y ago
    Can you actually name this number without looking in a dictionary? I cannot. Nine and a half zillions, I guess. So Alpha Centauri is like 44 zillion meters away; very enlightening.
    - Tomte 12y ago
      You can always invent a name (and "light year" is nothing else, just not based on a "round" number of meters). For example, since failure rates in safety engineering are usually pretty small and nobody wants to pronounce "something times ten to the minus eight" or similar, the term "fit" was invented to stand for 10^-9. (Although I admit that "failure in time" is a stupid name for a dimensionless constant) Similarly you could invent a "galactic length" or however you'd like to call it.
      - Mikhail_Edoshin 12y ago
        Light year is not just a name; year is a natural length of time and light speed is also a natural constant. The whole unit is natural and is based on things that make sense on such distances. This is same for all natural units; they grew up from usage. (This resulted in things that appears illogical, like having different with similar name for different applications, but this is only appearance. We measure water differently from oil or precious drugs and differently when we cook with water or build a dam, so it makes all the sense to have different units for different purposes.) Meters, however, have a different story; the meter was invented by some French scientist about the time they were changing everything after the revolution, including month names; somehow month names reverted back to normal, but meters stayed. The meter was initially defined as 1/40,000,000 of the length of a meridian. Here only the length of the meridian is natural to some extent, although I fail to see how it is relevant to what is normally measured with meters, and the constant is completely artificial.
endgame 12y ago
> I invite you to provide counterexamples, where the customary unit has an inherent advantage (familiarity does not count). I can't think of any. The only one I can think of is the nautical mile.
jandrewrogers 12y ago
All the unit systems are functionally equivalent but each generally have their own advantages. Chemical engineering 101 was learning to be fluidly unit agnostic. It is such a trivial skill that I do not see why it matters other than training people to do it. The nominal value of metric is that it is easy for back-of-the-envelope arithmetic. That is only true for abstract math because humans learn base-10 counting. There are many kinds of engineering systems, like chemical reaction kinetics or computer science, where base-10 counting systems have minimal relevance to back-of-the-envelope computation. I actually have designed a lot of physics-based representation software. It does not operate on metric models of reality even though it is translatable to metric units and presented that way to the end user for both input and output. In fact, a lot of sophisticated implementations represent all values as infinite intervals over the domain of integers with a strong preference for binary treatment because it is efficient. The presentation unit is almost irrelevant. Same with chemistry, which has its own archaic unit systems. Metric has a lot of practical advantages and disadvantages, depending on the use case. They are all trivial in real engineering scenarios.

by D_Alex 12y ago

Mikhail_Edoshin 12y ago

Cooking units are much better suited for the task than metric units. Typographic units are non-metric and metric units are inconvenient in typography, because millimeters are too big for character sizes and too small for page units and centimeters are both too big and too small at the same time. French (?) shoe sizes are numbered like 38, 39, 40, 41, etc. and the difference between these sizes are 2/3 cm, because it's a practical difference to mass-produce different shoe sizes. It's not metric, obviously. Parsecs are not metric. Heck, light years are not metric; and look at how rich the unit is, it tells you a lot about the distance. Try to express the distance to Alpha Centauri in metric units and comprehend it.

davty 12y ago
1 light year = 9.4605284 × 10^15 meters
- knodi123 12y ago
  heh, the numeric part is pretty much 3*Pi.
- Mikhail_Edoshin 12y ago
  Can you actually name this number without looking in a dictionary? I cannot. Nine and a half zillions, I guess. So Alpha Centauri is like 44 zillion meters away; very enlightening.
  - Tomte 12y ago
    You can always invent a name (and "light year" is nothing else, just not based on a "round" number of meters). For example, since failure rates in safety engineering are usually pretty small and nobody wants to pronounce "something times ten to the minus eight" or similar, the term "fit" was invented to stand for 10^-9. (Although I admit that "failure in time" is a stupid name for a dimensionless constant) Similarly you could invent a "galactic length" or however you'd like to call it.
    - Mikhail_Edoshin 12y ago
      Light year is not just a name; year is a natural length of time and light speed is also a natural constant. The whole unit is natural and is based on things that make sense on such distances. This is same for all natural units; they grew up from usage. (This resulted in things that appears illogical, like having different with similar name for different applications, but this is only appearance. We measure water differently from oil or precious drugs and differently when we cook with water or build a dam, so it makes all the sense to have different units for different purposes.) Meters, however, have a different story; the meter was invented by some French scientist about the time they were changing everything after the revolution, including month names; somehow month names reverted back to normal, but meters stayed. The meter was initially defined as 1/40,000,000 of the length of a meridian. Here only the length of the meridian is natural to some extent, although I fail to see how it is relevant to what is normally measured with meters, and the constant is completely artificial.

endgame 12y ago

> I invite you to provide counterexamples, where the customary unit has an inherent advantage (familiarity does not count). I can't think of any. The only one I can think of is the nautical mile.

jandrewrogers 12y ago

All the unit systems are functionally equivalent but each generally have their own advantages. Chemical engineering 101 was learning to be fluidly unit agnostic. It is such a trivial skill that I do not see why it matters other than training people to do it. The nominal value of metric is that it is easy for back-of-the-envelope arithmetic. That is only true for abstract math because humans learn base-10 counting. There are many kinds of engineering systems, like chemical reaction kinetics or computer science, where base-10 counting systems have minimal relevance to back-of-the-envelope computation. I actually have designed a lot of physics-based representation software. It does not operate on metric models of reality even though it is translatable to metric units and presented that way to the end user for both input and output. In fact, a lot of sophisticated implementations represent all values as infinite intervals over the domain of integers with a strong preference for binary treatment because it is efficient. The presentation unit is almost irrelevant. Same with chemistry, which has its own archaic unit systems. Metric has a lot of practical advantages and disadvantages, depending on the use case. They are all trivial in real engineering scenarios.