The metric system sucks
in [Math]
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From: Frogwatch on 3 Feb 2010 00:13 On Feb 3, 12:04 am, "Heidi Graw" <hg...(a)telus.net> wrote: > >"Bart Goddard" <goddar...(a)netscape.net> wrote in message > >news:Xns9D13CCB0DF19Egoddardbenetscapenet(a)74.209.136.81... > > "Heidi Graw" <hg...(a)telus.net> wrote in > >news:tC4an.64378$PH1.2203(a)edtnps82: > > >> He prefers the metric. It's easier to learn and easier to use. > >> I also prefer metric for those same reasons. > > > Which is also a reason for choosing Cosmetology school > > over Engineering. > > > B. > > <chuckle> ...and lots of folks do just that. A good question > to ask is, "How do you get the most using the least amount of > energy?" If cosmetology earns one an adequate living, and it > requires less energy and effort, then why not? > > Haven't you noticed that those who earn the most conserve > the most energy? Being an energy efficient person can be > rather quite profitable. ;-) > > Heidi The observation that various fields use variations on units is one of the great "Duh" lines in the original rant. I work in x-ray spectroscopy and routinely use eV for photon energy instead of the usual Joule simply because it is easy to relate this to how the x-rays are produced. Of course, I then convert to wavelength.
From: Andrew Usher on 3 Feb 2010 00:19 On Feb 2, 10:59 pm, Frogwatch <dboh...(a)mindspring.com> wrote: Obviously you can't use paragraphs ... > Whenever I need to do any calculations involving physical quantities, > I first convert to metric, do the calculation and then convert back to > english. This avoids bizarro conversions such as feet in a mile or > psi to something else. This practice is ridiculous and one of the things I complained about. It doesn't avoid any conversion; it only shifts them somewhere else (at best). > I even had one professor who worked in a system where all independent > constants (c, q, permativitty of free space, etc) were all equal to > 1. Those are useful - but they are not metric. > Using SI, you could then simply insert the correct units at the > end knowing it was correct with no conversions. You must be mistaken. If he truly was using natural units, you do need to insert conversions to get to SI units. If he was using purely mechanical formulae, then of course _any_ system of units is correct (because there are no constants between M,L,T in classical mechanics) - again I mentioned this in my essay. > In SI units, I can readily calculate things as varied as time to fall > to earth for an object, period of a pendulum, amount of fuel needed to > change an orbit, ALL IN MY HEAD. In english units, no way. Given that the formulae are exactly the same in English units, this makes no sense. > Let me see, 12 inches in a foot, 5280 feet/mile, a cubic foot of water > weighs ...........I dunno. However, a cubic meter of water is > obviously 1000 Kg. That works only for water, of course. > One does need to remember a few basic constants > such as c, q, mass of electron and proton, Avagodros number, etc. > However, in english units you would not only have to remember such > constants but also conversions between various units. How is that qualitatively different? > Ummmmmm, how do > you go from BTU/sec to hp? How is hp related to watts? If you need to know, you will know. That's the point. If you use Boltzmann's 'constant' (actually a conversion factor) frequently, you will remember the first few figures of it (I remember it as 10,604.5 K/ ev). > Calculating pressure, you say nobody does this, WRONG. I used to be > an oilfield engineer, the only way to deal with english units was to > memorize bizzaro conversions such as: > downhole pressure =.052*mudweight(pounds/gallon)*depth in feet. If I'm not mistaken, that number should be .134 , the number of cubic feet in a gallon . You just convert the density into slugs/cubic foot and then the simple formula works. If that .052 is correct, then there is some other modification being done - which would need to be done also in the metric version. And how is using that number any harder than using 9.8 in the metric version? > Somewhere in that .052 number is the constant g (what is g in english > units, something like 32 ft/sec/sec) but this formula gives no > physical sense of what is happening. In SI, one simply uses the > formula Pressure =rho*g*h where rho(density) is in kg/m3 and g is > about 10 m/sec2 and h is in meters. That formula isn't 'in SI'. It is universal and does not have units. > This formula in SI would be > useful on the moon where g is 1/6 of that on earth whereas I have no > immediate idea how to modify the english one (probably divide .052 by > 6 I think just to keep units correct). Certainly! The pressure is going to be 1/6 of what it is on Earth no matter what units you are using, that should be immediately obvious. > Quite frankly, the cumbersome english units cause so much confusion > that we would have far better of understanding of physical concepts if > we simply used SI in everything (except temp where we would use > Celsius). If you have trouble with concepts due to choice of units, then you don't really understand them at all. Andrew Usher
From: Andrew Usher on 3 Feb 2010 00:22 On Feb 2, 11:13 pm, Frogwatch <dboh...(a)mindspring.com> wrote: > The observation that various fields use variations on units is one of > the great "Duh" lines in the original rant. I work in x-ray > spectroscopy and routinely use eV for photon energy instead of the > usual Joule simply because it is easy to relate this to how the x-rays > are produced. Of course, I then convert to wavelength. Exactly! And I'm sure you don't go through Joules, etc., to do that. Instead you memorise the conversion you use, which is 12,398 ev-A. Is that easier just because it's 'metric'? (In fact ev are only half- metric at best.) Andrew Usher
From: Peter Webb on 3 Feb 2010 00:39 I needed to buy some chemicals for my pool. The man said I needed about 0.05% concentration. It was too much trouble to multiply 1.25m x 10m x 4m in my head to get 50 cubic metres of water = 50 tons so I would need about 2.5 kgs. Knowing that it doesn't make any difference to the calculation, instead I decided that my pool was 0.4 chains long, 1.6 chains wide, and about 0.4 chains wide. Then I multiplied this out, and converted to gallons capacity. Then I worked out how many ounces of the chemical I would need per gallon, multiplied it out, and divided by 16 to get the weight in pounds. Same thing.
From: The Chief Instigator on 3 Feb 2010 01:00
On Tue, 2 Feb 2010 17:44:47 -0800 (PST), Andrew Usher <k_over_hbarc(a)yahoo.com> wrote: > On Feb 2, 6:47?pm, "Heidi Graw" <hg...(a)telus.net> wrote: > >>?Btw, my own husband prefers >> the metric system. > > And why should his opinion matter, if he hasn't looked at it from the > perspective I have? > > Andrew Usher I bothered to learn both systems before I was out of elementary school (i.e., early 1960s), and I'd rather have "1.84 m" on my driver's license. Aside from that, we'll be a little cooler than usual for early February around here, around 14 C. (That's 57 F for the old-timers.) -- Patrick L. "The Chief Instigator" Humphrey (patrick(a)io.com) Houston, Texas www.io.com/~patrick/aeros.php (TCI's 2009-10 Houston Aeros) AA#2273 LAST GAME: Houston 3, Abbotsford 1 (February 1) NEXT GAME: Wednesday, February 3 vs. Peoria, 7:05 |