Timeline for Is the fact that 100 kPa equals about 1 atmosphere accidental?
Current License: CC BY-SA 3.0
27 events
| when toggle format | what | by | license | comment | |
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| Sep 30, 2022 at 12:19 | comment | added | SF. | The height of the Eiffel Tower as projected was 300m sharp. This changed over time as things were added on top, but the original 300m was an arbitrary choice of a round number. | |
| Sep 1, 2017 at 15:55 | comment | added | FumbleFingers | @SF.: I'd consider something like the Eiffel Tower to be a prime example of "engineering", but I seriously doubt any of the lengths or ratios used in its construction have any meaningful relationship with the number 10. It's simply not an inherently important number outside of the fact that all advanced countries now use it as their base for counting. Which itself only arises from the "happenstance" fact that "non-pentadactyl" vertebrates (with other than five "digits" on each limb) practically all got wiped out in one or more mass extinctions. | |
| Sep 1, 2017 at 13:37 | comment | added | SF. | @FumbleFingers: Well, I'm no theoretical physicist or pure mathematician. I'm an engineer. Nature doesn't favor powers of 10. Engineering (human creations) do. | |
| Sep 1, 2017 at 13:18 | comment | added | FumbleFingers | @SF.: Given that theoretical physicist and pure mathematicians are much concerned with things like sphere packing and Penrose tiling (where powers of 10 are about as relevant as powers of 123), I wouldn't make too much of multiples/powers of 10 favoured in areas (pun intended! :) such as "bulk" sale or transportation (if anything, they'd tend to favour powers of 2 simply because of the inverse square law as it relates to areas or volumes). | |
| Sep 1, 2017 at 13:04 | comment | added | SF. | @FumbleFingers: Well, systems of ancient egypt are longer-established. And they certainly were "everyday" units back in the day. Besides Benford's Law, there's plain psychology of preferring to pick round numbers when making arbitrary choice. Doorways being 180cm tall, as opposed to 176 or 181, shops selling wares in packages of 1kg as opposed to 947 or 1111 gram, etc. And then you arrive at results like average load per axis of a truck being a round number, because volume of the trailer is a round number so it fits a round number of items (dimensions being round) weighing a round number. | |
| Sep 1, 2017 at 12:57 | comment | added | FumbleFingers | @SF.: I said most long-established units! The metric system is a relative parvenu in the grand scheme of things (and still doesn't extend to everyday multiples such as days in a week, degrees in a circle, etc.). Besides which most of its more familiar "base units" (degree Celsius, gram, metre, etc.) are effectively either arbitrary or geocentric/anthropocentric. So there's no reason to expect multiples of things like that to have "universal" significance beyond that implied by Benford's Law (which applies equally in any base). | |
| Sep 1, 2017 at 8:56 | comment | added | SF. | @EralpB: This is if you analyze natural phenomena. Where it comes to engineering, where you deal with results of arbitrary decisions: dimensions chosen to be round numbers, helpful choices of "round" masses etc. (example of the latter: take your collection of kitchen vessels - pots, skillets, strainers, plates etc, and weigh them. You'll be surprised they have pretty "round" weights!) | |
| Sep 1, 2017 at 8:22 | comment | added | EralpB | @SF. okay you can choose one case to be the "round" multiple like pole to eq, but then the distance from pole to Z would be 1463 meters. Or you can select water's boiling temp to be 100 then Y's boiling temp would be 247. so.. it should work in some cases but I'm not sure how common that would be? | |
| Aug 31, 2017 at 23:01 | comment | added | SF. | @Lucian: One nanocentury is $\pi$ seconds, to within 0.5%. | |
| Aug 31, 2017 at 22:59 | comment | added | SF. | @FumbleFingers: "Most long-established "everyday" units are chosen on the basis of ratios / bases other than 10" - Maybe in your USA. Most of the world is metric, and uses metric system for "everyday" units. | |
| S Aug 31, 2017 at 20:46 | history | suggested | Kevin | CC BY-SA 3.0 |
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| Aug 31, 2017 at 20:12 | review | Suggested edits | |||
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| Aug 31, 2017 at 19:31 | comment | added | Lucian | Am I missing some hidden relation ? - Go to my profile page and read my motto. | |
| Aug 31, 2017 at 16:37 | comment | added | FumbleFingers | @SF.: Most long-established "everyday" units are chosen on the basis of ratios / bases other than 10 (inch / foot / mile, second / minute / hour, ounce / pound / stone, etc.). Factorisation is obviously important when setting ratios with those things, so maybe you could say there's some "fundamental (mathematical / geometric) significance" to numbers that come out "round" in those bases. But base 10 is effectively "anthropocentric", so there's no inherent significance to "10 to the power n" values (unlike "2 to the power n", say, for inverse square law contexts). | |
| Aug 31, 2017 at 16:08 | history | edited | Emilio Pisanty | CC BY-SA 3.0 |
Unit names are not capitalized; see the SI brochure for more details.
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| Aug 31, 2017 at 13:41 | comment | added | SF. | @FumbleFingers: Units are usually chosen such that they are powers of ten of "parent" units, or otherwise "round numbers" - like 10,000,000 meters being the distance from pole to equator; 100 Celsius degrees being the difference between freezing and boiling. It doesn't explain the natural world, it's just convenient to use. So most of "round" values of derived units you encounter in results of calculations are actually artifacts of these choices. But that's not always the case, plus when it is the case, the path the artifact arrived there is often non-obvious. | |
| Aug 31, 2017 at 13:23 | comment | added | FumbleFingers | ...actually, I'd be quite prepared to believe that there might be some deep underlying significance to natural world ratios/values that are "round" in terms of being exact multiples of some power of 3, so 9 might really be an important possibility above. And 11 might feasibly be "important" simply because it's a relatively small prime number. | |
| Aug 31, 2017 at 13:20 | comment | added | FumbleFingers | Maybe I'm missing something, but does "round" (in the sense of exactly divisible by some power of 10) actually have any meaning in the context of "explaining" the natural world? I can certainly see that such a concept might be relevant if we were talking about some power of 2, but apart from it's (pre-)historical significance as "most common number of digits on two (front) legs/arms in vertebrates", why should 10 be any more important than, say, 9 or 11? | |
| Aug 30, 2017 at 22:01 | history | tweeted | twitter.com/StackPhysics/status/903014779702439936 | ||
| Aug 30, 2017 at 21:53 | history | edited | Qmechanic♦ |
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| Aug 30, 2017 at 21:53 | history | protected | Qmechanic♦ | ||
| Aug 30, 2017 at 21:26 | answer | added | Sean E. Lake | timeline score: 26 | |
| Aug 30, 2017 at 20:33 | answer | added | Curd | timeline score: -4 | |
| Aug 30, 2017 at 17:54 | vote | accept | SF. | ||
| Aug 30, 2017 at 17:12 | comment | added | Steeven | It is not a completely round number, though: $$1\;\mathrm{atm}=101325\;\mathrm{Pa}\approx 101\;\mathrm {kPa}$$ | |
| Aug 30, 2017 at 17:12 | answer | added | Emilio Pisanty | timeline score: 44 | |
| Aug 30, 2017 at 17:03 | history | asked | SF. | CC BY-SA 3.0 |