10 ms·
This article (from downthread) suggests that 60 comes from the Sumerians, who had a base-60 number system, and 24 comes from the Egyptians, who had a base-12 nu
by jlebar 8y ago
This article (from downthread) suggests that 60 comes from the Sumerians, who had a base-60 number system, and 24 comes from the Egyptians, who had a base-12 number system. Although it agrees that 12 and 60 are conveniently divisible in the way you describe, I'm not finding any evidence to connect this specifically to sailors, or even to people dividing up shifts. Rather it seems likely that the civilization's numeric base was chosen first, and then it was applied to timekeeping.
https://www.scientificamerican.com/article/experts-time-division-days-hours-minutes/ https://www.scientificamerican.com/article/experts-time-divi...
- d0lph 8y agoLike natural selection at a cultural level.
- kungtotte 8y agoShipboard life was one of the first large scale applications of precise timekeeping. You need it for navigation and for organising shifts and jobs (though I think navigation is the major player here). For most people at that time there was no need for even hourly timekeeping, much less minutes or seconds. You woke up in the morning and ate your breakfast, milking the cows took however long it took, then you gathered the eggs from the hens, probably around that time you had lunch, then depending on the season you'd do whatever was needed in the fields until the sun started setting and then you ate supper. But with navigation you had to know how far to sail in any given direction to not get knocked off your course. I'm certain that the use of 60 and 12 base systems came from the Sumerians and Egyptians, but their application for timekeeping is probably influenced heavily by sailors.
- derefr 8y agoIt seems like even without precise knowledge of absolute time, precise knowledge of intervals would be useful; you could evaluate a time-trial to know if you’re improving as a footman/chariot rider; you could evaluate the maximum speed of a horse; you could measure height by dropping things off of the sides; etc. So I would expect that, even if we didn’t have hours, we probably had second and minutes fairly early on.
- gowld 8y agoYou don't need any particular units for that, though. Any periodic oscillator you have at hand would work. (And with an analog clock you don't need to name the subdivisions, just look at the clock). You only need standard units with nice divisions for mass-coordinated scheduling.
- anchpop 8y agoHow will you develop an equation that maps time-to-fall to height without some consistent unit for time?
- jessaustin 8y agoJust keep the same periodic oscillator around for all of your experiments? Of course, if someone else wanted to reproduce those experiments, she would be using a different oscillator than you, but the same one for all of her experiments. She's probably dropping things from different heights anyway. The theory doesn't actually depend on units of time. The specific value of a constant like G does depend on that, but by the time engineers need to use that they have probably built real clocks.
- derefr 8y agoOr mass-coordinated record-keeping for something like the Olympics. How do you know whether this year’s best runner beat last year’s best runner?
- RobLach 8y agoBoth could be true. Those particular numerical systems would have started in those cultures and would have existed amongst many but other groups would have adopted the ones that made most sense in their field and consequently solidified their usage. Kinda like any open standard; ultimately it’s a popularity contest.