On Mon, 02 Dec 2002 17:01:21 John David Galt wrote: >> It's time for a new kilogram standard, researchers say _ one that won't >> depend on the vagaries of a single chunk of metal. So physicists are >> striving to replace le grand K with a fundamental physical measurement to >> last forever. > >I agree. Let's remove a subtle but annoying inconsistency from the system >by defining the kilogram to equal exactly the mass of 1000 cc of water at >4 deg C. (The old kilogram comes out to 1000.028 cc, so this is a change >but a minor one.) > Sorry to rain in your parade (once again, I'm afraid...), John, but the above proposal does NOT work. Other physical factors come to play in this type of definition, plus the difficulty of logistics, environmental controls and operational restrictions associated with the above.
This type of proposal is just as flawed as the one that derived the hideous calorie. Defining units based on environmental constraints is (unfortunately) just a 'passi' philosophy the modern scientists have already abandoned many years ago. >All the SI units are supposed to be interrelated this way. Let's make it >true by making this change. Effectively this means that the radiation >wavelength that defines the meter will now define the kg as well. >... On the other hand I personally favored the older definition of the meter simply because it was more consistent with the modern philosophy/framework of defining units 'sola definitia', i.e. that would not be dependent on any other SI unit or property, that would stand alone by itself (even though I concede that there are other SI units that are defined in not such "kosher" ways...). IMHO the move to use the speed of light for the definition of the metre was an extremely grave *philosophical* mistake! Unfortunately correct framework philosophy gave way to higher accuracy, and I'm still unconvinced that it was *absolutely necessary* to compromise this vital principle of metrology. But then again, many of us here how many fundamental flaws still plague the SI system (the time construct being just one of many)... Marcus ____________________________________________________________ Get 25MB of email storage with Lycos Mail Plus! Sign up today -- http://www.mail.lycos.com/brandPage.shtml?pageId=plus
