Wikipedia:Reference desk/Archives/Science/2019 April 20

= April 20 =

TFA?
See Wikipedia talk:Featured articles. --Guy Macon (talk) 15:31, 20 April 2019 (UTC)
 * I'm not sure what you're going for. Are you asking us to evaluate the article 2019 redefinition of SI base units? That's not something we generally do - there's a whole other project for that. It's not like the article is hurting for references. The {who?} tag is going to attract attention if you're trying to get it passed. Matt Deres (talk) 21:10, 20 April 2019 (UTC)


 * So, after May 20 the mass of one mole of a substance is no longer equal to the molecular mass times gram/Dalton? Count Iblis (talk) 00:53, 21 April 2019 (UTC)
 * And yet the baseball pitching distance will remain 60 feet 6 inches. ←Baseball Bugs What's up, Doc? carrots→ 04:31, 21 April 2019 (UTC)
 * Well, an inch is formally defined as 2.54 centimeters... 93.136.86.241 (talk) 02:01, 23 April 2019 (UTC)
 * True but the definition change of the metre is very minor though, the definition of the second has additional rigour. The big change for the metre and so the inch and foot and so the baseball pitching distance was in 1960 and 1983 although of course these intentionally didn't really affect the length and while there were good reasons for them they don't affect stuff like measuring the baseball pitching distance in a meaningful way. I mean I don't know how laser distance measurers are produced and calibrated but I doubt it would be different of the definition was still based on an artifact rather than the distance travelled by light in vacuum. Nil Einne (talk) 02:16, 23 April 2019 (UTC)
 * American base units like inch, pound and pint are all defined in terms of SI units, so they'll all be affected as little or as much as the SI units. So the appeal to good ole common sense units doesn't work here. I'm well aware all the changes discussed are 100% irrelevant to everyone making baseball fields, cement bags, beer bottles... 93.136.86.241 (talk) 02:53, 23 April 2019 (UTC)
 * "so they'll all be affected as little or as much as the SI units" - yes that's what I meant. But we were only discussing feet and inches, so the more major change to the definition of the kilogram is irrelevant to this subthread. No one said Baseball (ball) "". The only point of discussion was length, and the change to the definition of length is extremely minor. As I said, you have to go back to 1983 and 1960 for the substantial changes but we're only discussing the 2019 redefinition. The metre etc are clearly the common sense units, so I would argue an appeal to common sense units does work. This is incredibly offtopic though. Nil Einne (talk) 16:30, 24 April 2019 (UTC)
 * I'm not sure if the change is really "that" important, but if I understand correctly it has the major appeal of getting rid of a tremendously unsatisfying notion of the "ampere". Now the electron or proton charge is defined as 1.602176634E−19 coulombs (= ampere * second).  So 1 coulomb = about 6.24150907E+18 elementary charges, and 1 mol of elementary charges is now exactly 6.02214076E+23 elementary charges, so with a better calculator than Google, (or a virtuous exercise of long division) an ampere can be worked out to an exact repeating decimal that starts as something like 1/964853.321 = .0000103642697 mol charge per second.  Now all we have to do is get them to start relabeling the 10 amp breakers as 100 umol/s breakers and we should be golden.  Can't wait to nail shut the coffin on that "basic unit". Wnt (talk) 21:23, 21 April 2019 (UTC)


 * Shameless plug (but I am plugging a proposed improvement to Wikipedia, so this is allowed): The 2019 redefinition of SI base units is scheduled to happen on 20 May 2019. I would like it to be Today's featured article on that day. To make this happen, it needs everything listed at Featured article criteria (some of which it already has), followed by a nomination at Featured article candidates, then a nomination at Today's featured article/requests. Any help improving the article would be greatly appreciated. --Guy Macon (talk) 18:07, 23 April 2019 (UTC)