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  • I find imperial vs metric to be a question of practicality vs ideality, and as an engineer I tend towards the former. Either way it doesn't really matter, because unit conversions are easy math, and a good engineer can work in any unit system.

    In defense of imperial, to balance things out here:

    • I almost never need to go from inches to feet to yards to miles. Conversions like that play almost no role in my daily life. Easily going from mm to cm to m to km is a solution in need of a problem.
    • Because imperial isn't bound by a constant conversion factor, you can use several points of reference. An inch is about the size of one knuckle. A foot is roughly the size of... A foot. Most of the time, I don't need anything more than this. Although to be fair, I rarely need this even. Smaller than an inch is all metric though, easily.
    • Imperial is sometimes more convenient. Twelve seems like an usual number for inches to feet, but twelve is also easily divisible by 2, 3, 4, and 6. I can instantly convert from fractional feet to inches for the most common fractions.
    • I'm going to say it, both temperature scales make sense. Celsius being based on water makes a lot of sense, it's the most ubiquitous substance. Fahrenheit makes sense too in terms of climate and the weather that people experience -- it's harder to go more simple than 0 = very cold and 100 = very hot.
    • Conversions actually aren't universally good for metric. Joules are great for abstract concepts, but not so much more realistic matters. The energy required to raise 1 g of water by 1 deg C is 4.184 Joules -- or more simply, 1 calorie. Calorie is actually neither imperial nor metric. Metric here loses the intuitiveness of water, while SI takes a big W. Another example, mass and weight. In metric, 1 kg is 9.8 Newtons. Most places don't bother with Newtons and stick to kg. In imperial, 1 pound mass is 1 pound weight. They have been set equal to each other by definition. Mass to weight calculations will always be much easier in imperial, and that's rather nice for looking at chemistry and flowrates and equipment requirements.
    • Imperial is better for K-12 education, another unpopular opinion. It requires children to learn going from inches to feet to yards, which uses math far more regularly than metric does. For lengths, it's great for teaching fractions. Unit conversions between systems are taught often, which gives students a basis when you're converting other units, like moles and kilograms in chemistry.
    • It teaches you to always label your fucking units. It's incredibly bad engineering practice to do this, even if you work solely in one unit system, because you almost certainly aren't using just one unit. Hell when it comes to pressure, with kPa, psi, atmospheres, and bar, it really doesn't matter what unit system you're using.
    • Metric defines some units in a way that's good for science but bad for everyday life. A pascal is 1 newton of force per square meter. Our atmosphere is 101,125 Pascals. You see kPa used constantly because the defined unit is absurdly small. The same goes for a Joule, it's the work done to move a 1 newton object 1 meter. Chemical reaction energy is measured on the basis of kJ per mole (or kg). The defined unit is really small.

    TLDR: Convenience + Practicality vs Ideality + Logic

    • The amount of downvotes for a thoroughly explained opinion tells me this is Reddit now.

      • Yeah it's disappointing. Several weeks ago, it would've been upvoted not because people agreed with it, but because it contributed to a thoughtful discussion. I'm an engineer. I've probably had to explicitly consider and think about units more in a year than most people here have in their lifetimes.

        I just can't wrap my head around this thread. You'd think Americans were math geniuses by age 12 with how hard they're making this out to be.

        • To help you out, because you seem confused, you’re not being downvoted because “lemmy has become reddit”, you’re being downvoted because literally everything you said is just spectacularly wrong. You’re not “thoroughly explaining” anything, you're spreading misinformation.

          I almost never need to go from inches to feet to yards to miles. Conversions like that play almost no role in my daily life. Easily going from mm to cm to m to km is a solution in need of a problem.

          People do that every day, be it in their professional or personal life. It’s the same physical property, and your definitions of “feet” and “mile” are as arbitrary as anyting. You’re simply not converting units in imperial, because it’s such a hassle people don’t bother. Look in this thread, people cannot even add up short distances to a longer distance, and then they start shouting “YOU DO NOT MIX IMPERIAL UNITS” only to proceed giving their height as “5”6’”.

          In metric you don’t “convert”. It’s all the same unit. That is the point.

          And how is it not relevant if I know that if I walk a pace of 6 km/h it takes me 15 min for the 250 m to the next bakery and then another 2 h to my friend in the next village 12 km away?

          If I have a slab of meat saying “2.5 kg” and I have 10 guests, can I offer each guest a 250 g steak? Yes. I can. Easy.

          These are literally every day questions, to say otherwise is just either completely ignorant of bad faith. Adding small things up to large things or dividing large things into small things is something people do, and being stuck in one arbitrarily defined unit without the option to scale this unit is abolutely not a feature.

          Because imperial isn't bound by a constant conversion factor, you can use several points of reference. An inch is about the size of one knuckle. A foot is roughly the size of... A foot.

          That is another issue, not a feature. My knuckle is 3.5 cm, that’s 38% percent more than an actual inch. Only about 2% of men have a foot that’s actually the size of a “foot”, the majority of women have a foot that is less than 80% of a “foot”.

          Most of the time, I don't need anything more than this.

          Good for you, but you’re not alone on this world, hence standardized units. Nobody keeps me from using the span of my thumb and index finger (20 cm) as a unit of measure. But if I want to do something, anything that involves other people, that's just as useless as it gets.

          Imperial is sometimes more convenient. Twelve seems like an usual number for inches to feet, but twelve is also easily divisible by 2, 3, 4, and 6. I can instantly convert from fractional feet to inches for the most common fractions.

          But it’s not consistent and you’re not using a “dozenal” system, you’re just counting to 12 in decimal. Or 16. Or 8. Or 3. Depending on the unit. That’s why you’re ending up with completely unwieldy numbers, e.g. 1 cubic foot is 1728 cubic inches, and now tell me again how “instantly” you can come up with 1/8 of a cubic foot in inches.

          Fahrenheit makes sense too in terms of climate and the weather that people experience -- it's harder to go more simple than 0 = very cold and 100 = very hot.

          How does that make sense? How is 100 °F “very hot”? If I take a shower that’s lukewarm and a sanitary issue. If you’re cooking that’s not even a temperature where you can cook. So why didn’t you come up with a “simple” unit that makes sense for cooking? And for showering? And for deep freezing? And…

          The energy required to raise 1 g of water by 1 deg C is 4.184 Joules -- or more simply, 1 calorie. Calorie is actually neither imperial nor metric.

          Wrong. Seriously, you just said it it yourself “1 g of water by 1 deg C”, of course it’s metric. It’s an official CGS unit since 1896. It’s not an official SI unit, that doesn’t make it “not metric”.

          In metric, 1 kg is 9.8 Newtons. Most places don't bother with Newtons and stick to kg. In imperial, 1 pound mass is 1 pound weight. They have been set equal to each other by definition.

          Mass is not weight, and for rule of thumb calculations you can assume 10 N. For more precise calculations you would be using a calculator anyway and should also probably consider the local gravity, which on earth can vary by IIRC nearly 1%. “1 pound mass is 1 pound weight” is only valid at the point on earth where the pound was defined, its not 1:1 at the Equator, in Northern Europe, etc.

          Imperial is better for K-12 education, another unpopular opinion.

          Opinion, source needed. Judging by the fact that the US frequently ranks much lower than many of the EU countries (let alone Asia) when it comes to math education and, again, several people in this very thread demonstrate they can’t add up or divide anything beyond the respective unit I doubt that.

          It teaches you to always label your fucking units.

          That has absolutely nothing to do with imperial or metric or whatever. You always need to do that. Saying I just drove 100 and than walked a 100 more is a useless figure in any system.

          It's incredibly bad engineering practice to do this, even if you work solely in one unit system

          And yet you already failed to do so above when you brought up Fahrenheit.

          Metric defines some units in a way that's good for science but bad for everyday life. A pascal is 1 newton of force per square meter. Our atmosphere is 101,125 Pascals. You see kPa used constantly because the defined unit is absurdly small. The same goes for a Joule, it's the work done to move a 1 newton object 1 meter. Chemical reaction energy is measured on the basis of kJ per mole (or kg). The defined unit is really small.

          See, and this makes me doubt me you have understood anything at all about either the metric system, the imperial system, or SI prefixes.

          Every unit has an “arbitrary” definition by definition. What’s a “mile”, that’s not a useful measure for my feet, let’s invent a new unit called “feet”, and so on and so on. That doesn’t change for metric. A “meter” is not useful to measure the distance to the next village either.

          The goal of prefixes is to resolve the issue of constantly having to add new units with another completely arbitrary definition for the same physical property. That’s not “bad for everyday life” that’s absolutely genius.

          What is a “mile” supposed to be? I can’t touch that. You can show me two points on a field, great. How does it relate to feet? “We don’t need that”.

          With SI prefixes you can just scale any unit to whatever magnitude you need, and it’s still the same unit. You can take one step, say “okay, this is one meter, if I take 1000 steps thats a kilometer”. And if the definition of a “meter” would be what we call “kilometer” it wouldn’t bother anyone, because then we just would take a step and say “okay, this is one millimeter”.

          You do the same with imperial, except that at some random point where it get's unusable you just invent something completely unrelated and say "good job that man".

          It’s absolutely baffling that an engineer apparently doesn’t understand why it’s absolutely helpful – for every day life as well as science – to have only the most fundamental physical properties defined and to be able to scale these definitions with absolute ease to the magnitude at hand without having to “convert” them.

          • Either way it doesn’t really matter, because unit conversions are easy math, and a good engineer can work in any unit system.

            In defense of imperial, to balance things out here:

            It's baffling that someone would spend so long on a critique while completely missing the point. My argument has never been that imperial is better than metric. I regularly use both, and there are advantages and disadvantages to both. The advantages of metric here have been covered ad nauseum, so there was no need for me to mention them again. And since engineering is a field that intimately deals with both unit systems, I thought it would be good to offer that perspective

            I was clearly right to offer that perspective, because the majority of your argument focuses on ideality and exactness. Engineering doesn't deal with ideality or absolute precision. A scientist uses just the right amount of tape to patch a hole. An engineer eyeballs it, adds more tape as needed, and calls it good enough. I don't need my feet to exactly be 1 imperial foot or for my knuckle to be exactly 1 imperial inch. As long as it's within 75-125% of it, I've got the right ballpark. And if it's closer to 50% or 150%? I can do simple math to scale it.

            Thank you for illustrating my point on how this thread is an emulation of Reddit, complete with arrogant arguments which miss the OP's point and also fundamentally misunderstanding their perspective. Plus, not even understanding parts of their argument apparently -- I didn't label 0 or 100 when talking about temperature because I was talking about the abstract number itself. That should have been obvious from me talking about the simplicity of using 0 for very cold and 100 for very hot.

            • It’s baffling that someone would spend so long on a critique while completely missing the point.

              It's baffling that you spend many many paragraphs on this but people who disagree with you are "missing the point"... Well of course they are...

              And since engineering is a field that intimately deals with both unit systems,

              I'm an engineer, and have been for many years. I have never "intimately dealt" with both systems. You are again just speaking for a minority.

              because the majority of your argument focuses on ideality and exactness. Engineering doesn’t deal with ideality or absolute precision.

              You're accusing me of missing the point yet it's you who is completely missing the point over and over again. The argument is not about exactness, that is not a property of any unit system. Literally nothing what I wrote is about "absolute precision", and you completely fail to understand that.

              The argument focuses, in fact, on practicality. It is vastly more practical to have just one unit for the physical property of "length" instead of a zoo, it is vastly more practical to have consistent prefixes to "shift" that unit around to make it more appropriate for the task at hand, instead of having to resort to another completely unrelated unit measuring the same thing. It's easier to understand, easier to memorise, easier to calculate.

              The imperial system is not practical, there are no advantages to speak of. If it were an actual duodecimal system, that would be a point, but it isn't.

              A scientist uses just the right amount of tape to patch a hole. An engineer eyeballs it, adds more tape as needed, and calls it good enough. I don’t need my feet to exactly be 1 imperial foot or for my knuckle to be exactly 1 imperial inch. As long as it’s within 75-125% of it, I’ve got the right ballpark. And if it’s closer to 50% or 150%? I can do simple math to scale it.

              Okay, whatever kind of engineer you think you are, that's just not how the world works. Like I said, I'm an engineer as well, having an absolute deviation of 50% is not "engineering", it's recklessly bumbling around. It's an insult to any engineer.

              G'day.

465 comments