• ChaoticNeutralCzech@feddit.de
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    1 year ago

    Sure. How much does water in a 1ft × 2ft × 3ft aquarium weigh?

    In metric, an equivalent calculation is 30 cm × 60 cm × 90 cm = 3 × 6 × 9 dm^3 = 162 𝑙 ≡ 162 kg of water, and if you’re pedantic, the weight is around 1620 N or closer to 1590 N for 𝑔 = 9.8 m·s-2. All calculated in my head.

    • oatscoop@midwest.social
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      1 year ago

      A cubic foot is 7.48 gallons, close enough to 7.5. 1 gallon of water is 8.33 lbs ≈ 25/3.

      6 * 7.5 = 45 gallons

      45 * 25/3 = 375 lbs – easy mental math. Sure, the “accurate” answer is 373.87 lbs, but the aquarium probably isn’t filled with distilled water, perfectly dimensionally accurate, or filled to that exact capacity.

      • RaivoKulli@sopuli.xyz
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        1 year ago

        A cubic foot is 7.48 gallons, close enough to 7.5

        1 gallon of water is 8.33 lbs ≈ 25/3.

        25/3

        Oh god this is what we mean

        • kurap1ka@lemmy.world
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          1 year ago

          Oh just wait until you see imperial hex screws. In metric you get them in screwdriver size relating to mm. US hex screws are like 16/64 of an inch or 5/16 of an apple. And of course they don’t relate to metric at all and you can’t use the same tools.

          • ChaoticNeutralCzech@feddit.de
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            1 year ago

            Or fucking AWG. Higher number means smaller diameter wire, and Americans are afraid of decimal or negative numbers so large diameters are 00, 000 etc. The formula is batshit insane
            𝑑𝑛 = 0.005 in × 92^(36 – 𝑛)/39^
            so people just use a lookup table.

            • ultracritical@lemmy.world
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              1 year ago

              Gauge is historically number of passes through gauging machine. With the machine and material in question being different for every single one. We took that and put it to a standard, so it’s super messy and makes no sense.

              • ChaoticNeutralCzech@feddit.de
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                1 year ago

                Well, I wonder what kind of gauging machine can do -3 passes for 0000 wire… /s

                Too bad AWG is so ubiquitous it’s starting to creep into Europe.

        • ultracritical@lemmy.world
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          1 year ago

          It’s only arbitrarily easy since water has a density of 1 kg/l in metric, as it was designed to do so. If you happened to know the density of water is 62.2 lb/ft^3 then the equation is roughly 123*60 which is 360 lb. 372 if you can actually paid attention to what common core was trying to teach. If the material was anything other then water the math would be just as difficult to do in imperial or metric.

          Metric is still far superior as the harmonized units make density in particular much easier to convert between. About the only thing imperial is better at is thread pitch of screws. I will also maintain that when describing human temperatures for weather Fahrenheit is a superior scale, but that’s just more personal preference and experience then any rational basis.

          • RaivoKulli@sopuli.xyz
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            1 year ago

            It’s only arbitrarily easy since water has a density of 1 kg/l in metric, as it was designed to do so.

            it was designed to do so

            That’s also what we mean

            I will also maintain that when describing human temperatures for weather Fahrenheit is a superior scale

            That’s one where I’d say it’s almost entirely personal preference. Water freezing being at zero is handy because it’s nice to know when there’s ice/snow outside, but that’s also something you could just learn to remember in Fahrenheit too. Doesn’t really matter with that system. Kelvin and Celsius being bros is nice but it’s extremely rare that I use that so eh.

        • ChaoticNeutralCzech@feddit.de
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          1 year ago

          I wonder how many people know these numbers. With the level of US education, probably 10%. Not to mention, most quantities will not be exact feet, more like 2’5". Good luck multiplying that, at least 74 cm is easy to type into a calculator.

          Anyway, if you ask a European how much a liter of water weighs, 95% will say “a kilo” without much hesitation.