On May 20, 2009, at 1:31 PM, der Mouse wrote: >>>>> ~5 tons, enough for a 3000 sq ft house. >>>> And neither makes dimensional sense ;-) >>> 1 ton refers to the equivalent cooling power as melting 1 ton of >>> ice - >> Still not dimensionally right. Need time in the denominator. > > Yes - "per hour". A ton of cooling is 12 Kbtu, about the heat of > crystallization of one ton of water, per hour. > >> Why do engineers use so many whacky units? Why pretend Rumford and >> Joule never existed? What's wrong with watts? > > The same reason people will say "a bulb shedding about 40 watts of > light" when they really mean "about the light given off by a > bog-standard 40-watt light bulb" (meaning maybe as much as 6 watts of > light). The same reason people still occasionally cite weight in > stones. The reason people say thing like "weighs about two kilos" > even > though "two kilos" is a mass, not weight, measurement. The same > reason > machine screws are still sized with small integers (as in the 6 in > "6-32") rather than overt measurements. > > That is to say, tradition and convenience.
Good excuses for the masses. Not so good for engineering, which depends on precise communication. Crashing a spacecraft into Mars is pretty inconvenient, and we'd prefer not to make a tradition of it. > > /~\ The ASCII Mouse > \ / Ribbon Campaign > X Against HTML [email protected] > / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B > > > _______________________________________________ > geda-user mailing list > [email protected] > http://www.seul.org/cgi-bin/mailman/listinfo/geda-user > John Doty Noqsi Aerospace, Ltd. http://www.noqsi.com/ [email protected] _______________________________________________ geda-user mailing list [email protected] http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
