Talk:International System of Units/Archives/07/2014

Am missing the most important aspect of measurement and units, which should be placed in the introduction.

A unit, is derivative unit, as are many another, however

The correct phrase to use is, a unit is a PARCIAL derivative unit, as are many another, the form and manner of obtaining these units is in measuring the differencial while the other variables are held constant, which, defacto, is a parcial differencial calculation.

Most any misses this smallish very, very, very important detail, the combined inverse calculations having to cope with as many parcial derivative equations as there are variables, including multiple constants that will not show up in the combined unit.

An example:

f(w,x,y,z)=w*x^y + z

Parcial derivatives ∂f/∂w: x^y ∂f/∂x: y*w*x^(y-1) ∂f/∂y: ln(x)*w*x^y ∂f/∂z: 1

Are all individual units with solely one unit, z, being an end basic unit.

For some interested party to figure out how to parcially diferenciate ∂f/∂w, ∂f/∂x, ∂f/∂y into basic units.

Note: log(x,x)=1, log(x,e)=ln(x), and overall it does not much matter which log base you use to differenciate ∂f/∂y, therefore ln(x) might as well be logbase x, which makes that log=1 leading to w*x^y being the parcial derivative of itself with respect to y, and therefore not really seperable unless you can remove the y axis (set that to zero origin), which forces x to one, leading to w at (w,x,y,z)=(w,1,0,nc), which is a vector space removed from a joint (0,0,0,0) origin. — Preceding unsigned comment added by 201.248.123.72 (talk) 16:01, 6 July 2014 (UTC)

No. "Derivative" here is in the sense of "derived from the base units" (see "derive") not in the mathematical sense. Djr32 (talk) 21:58, 6 July 2014 (UTC)

Biased article?

The SI/metric system is very inconsistent with milli-, deci-, hacta-, kilo- used inconsistently and arbitrarily. Kilogram, not gram, is the base unit. Also the "special" unit names like liter, bar are used inconsistently. Some units are decimally based, but time isn't and angle isn't. Also this article does not talk to any of the difficult history of the SI or metric. The US won't adopt it, Canada are gradually losing it.

Why is none of it there? Why is the article very biased? Can we clean it or warn readers it is not reliable please. — Preceding unsigned comment added by Boris.schmidt (talk • contribs) 13:07, 13 July 2014 (UTC)

How is the article biased? What is it biased in favour of? How are the prefixes used inconsistently? Angles measured in radians are essentially dimensionless; degree measures are accepted but not SI units. Canada officially uses the SI for almost all measures although some people may still use the British system by converting from metric units. Dger (talk) 20:27, 13 July 2014 (UTC)

I said already how the article is biased. It doesn't precise the inconsistent use of units names prefixes. It doesn't precise that the "special" units names are given because peoples don't like long difficult unit names. It doesn't precise that decimal has bad precision in digital computers which work better with binary/octal/hexadecimal number systems. It doesn't precise that the peoples don't use SI they use half-kilo, quarter-kilo, pound, hours, minutes, degrees. It doesn't precise the difficult history of the SI/metric system. It makes it like the metric systems is perfect and with no problems which is biased. Canada is now again making more use of the old measures and not the metric. And the UK too doesn't use the metric for the normal people, just for the science and the bureaucracy and the schools.

The inconsistency in the names prefixes is they aren't used usually. 1 hectogram is written the wrong way as 100g and 1 decagram is written 10g. But kilogram is the base unit so it must be 1 decikilogram and 1 centikilogram. No? 100m is 1 hectometre but it is never written. 10m is 1 decametre. Are you understanding my points?

I'm not, so let me put it this way: How would you propose to improve the article? Please be specific. Jonathunder (talk) 22:27, 14 July 2014 (UTC)

This seems to be adequately addressed in the relevant footnote, which reads:

• "Despite the prefix "kilo-", the kilogram is the base unit of mass. The kilogram, not the gram, is used in the definitions of derived units.
  Nonetheless, units of mass are named as if the gram were the base unit."

I don't see what this has to do with bias.

--Boson (talk) 09:39, 15 July 2014 (UTC)