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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

467 comments