3 ms·

"Customary units" are a varied bunch. The inch-foot-yard-mile scale are not uniform, and not easy to calculate. Their only convenience is easy divisibility by

by nine_k 10mo ago

"Customary units" are a varied bunch. The inch-foot-yard-mile scale are not uniform, and not easy to calculate. Their only convenience is easy divisibility by 3. The practical example of uniform scale of this kind is seconds-minutes-hours, which, I suppose, go all the way down to the Sumerian 60-based scale. The mm-cm-m-km are much easier in practice. Sub-inch units are an honest binary system, and as such is pretty practical. The fact that it's written as a ratio of decimal numbers is sometimes unhelpful though, comparing 7/16" and 1/2" takes either mental gymnastics or memorization. Millimeters are somehow more convenient here, but not by such a large margin as with inch-foot-yard scale. The Fahrenheit scale is uselessly arbitrary; 0°F does not match anything useful, and 100°F is not that useful either. The only mile that makes sense is the nautical mile, 1 nm matches 1" of arc on the map / globe, the same way as 1 km is 1/40,000th of the arc.

AngryData 10mo ago
0F is useful in areas where they salt roads because thats the temperature many salts stop being effective and previously good road might turn to ice sheets. But it isn't a good reason all by itself.
- fragmede 10mo ago
  How hard is it to remember -17° C when that's something you grew up with since childhood though? As a trade off, you get 0° C for water freezing and you don't have to remember 32°F for water freezing instead. Or you remember all 4 of those if you leave near a borders.
  - AngryData 10mo ago
    I would argue that -17C for brine water is far more difficult to remember than 32 for pure water freezing, 32 is an incredibly common number in fractional measures, but I will concede the point because that seems like more of a happy accident than intent. The biggest problem I have is I don't see either as inherently better, both are relative scales defined by easy to setup but completely arbitrary measures that lacks any real relevance to modern life. We could of defined or scaled our thermometers based on the boiling and freezing points of mercury and nothing would really change, just shifting some numbers around and then still making another absolute scale that can actually be used for any sort of decent thermal calculations.

by nine_k 10mo ago

AngryData 10mo ago

0F is useful in areas where they salt roads because thats the temperature many salts stop being effective and previously good road might turn to ice sheets. But it isn't a good reason all by itself.

fragmede 10mo ago
How hard is it to remember -17° C when that's something you grew up with since childhood though? As a trade off, you get 0° C for water freezing and you don't have to remember 32°F for water freezing instead. Or you remember all 4 of those if you leave near a borders.
- AngryData 10mo ago
  I would argue that -17C for brine water is far more difficult to remember than 32 for pure water freezing, 32 is an incredibly common number in fractional measures, but I will concede the point because that seems like more of a happy accident than intent. The biggest problem I have is I don't see either as inherently better, both are relative scales defined by easy to setup but completely arbitrary measures that lacks any real relevance to modern life. We could of defined or scaled our thermometers based on the boiling and freezing points of mercury and nothing would really change, just shifting some numbers around and then still making another absolute scale that can actually be used for any sort of decent thermal calculations.