Hi,
The kilogram is still defined to be the mass of an iridium-platinum cylinder kept in (I think) Paris. It is the only basic unit not defined by an operational definition. It would be simple enough to define it as some number of atoms of some element, but the technology for measuring the number of atoms is still not as precise as the direct comparison of two masses.
True, but that has nothing to do with being metric. For instance, take the number of oscillations of whatever frequency is used to define the meter. Calculate how many oscillations there are in 25.4 mm. That's your definition of an inch.
What you are overlooking here is that the imperial system is not the only other system around. There are many units, especially in science and engineering, that are (or were) used because they made sense. Things like star masses in terms of the solar mass, atomic mass units for atom and molecule sized units, bars for pressures from one atmosphere to about a million or so, mm of Hg for low pressures and vacuum (it even has a name, I believe the mm of Mg is the torr), barns (and sheds and doghouses) for atomic cross sections, etc.
I am not against using SI units (or any other system). I am against the 'you must use metric units for everything' mentality of the metrication morons.
Oh, and Celsius is easy. Water freezes at zero, comfortable room temperature is 20 or 21, normal body temperature is 37, and 40 is too damned hot to do anything. Remember those four points, and you've pretty much got it covered.
--Pete
(09-16-2010, 06:21 AM)Klaus Wrote: I find it odd that the kilogram is what they define to be such-and-such (used to be the mass of a reference object, but didn't they fix that?), but it's still a "kilo"-gram. So, really, the "base" unit is the gram, even tho the defined amount is 1000 of them. The CGS systems were equally weird, because they used the "centi" version of a unit as the base. :-P
The kilogram is still defined to be the mass of an iridium-platinum cylinder kept in (I think) Paris. It is the only basic unit not defined by an operational definition. It would be simple enough to define it as some number of atoms of some element, but the technology for measuring the number of atoms is still not as precise as the direct comparison of two masses.
Quote:What I like about the SI units is that they are defined in terms of measurable things - so many oscillations of a cesium atom, so many wavelengths of a particular color of light, etc.
True, but that has nothing to do with being metric. For instance, take the number of oscillations of whatever frequency is used to define the meter. Calculate how many oscillations there are in 25.4 mm. That's your definition of an inch.
Quote:Where I do take issue with using traditional units is when you're doing anything especially scientific. There's no reason to use slugs and feet when you're planning an orbit around mars.
What you are overlooking here is that the imperial system is not the only other system around. There are many units, especially in science and engineering, that are (or were) used because they made sense. Things like star masses in terms of the solar mass, atomic mass units for atom and molecule sized units, bars for pressures from one atmosphere to about a million or so, mm of Hg for low pressures and vacuum (it even has a name, I believe the mm of Mg is the torr), barns (and sheds and doghouses) for atomic cross sections, etc.
I am not against using SI units (or any other system). I am against the 'you must use metric units for everything' mentality of the metrication morons.
Oh, and Celsius is easy. Water freezes at zero, comfortable room temperature is 20 or 21, normal body temperature is 37, and 40 is too damned hot to do anything. Remember those four points, and you've pretty much got it covered.
--Pete
How big was the aquarium in Noah's ark?