Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: syhprum on 23/10/2006 08:37:56

Title: SI units
Post by: syhprum on 23/10/2006 08:37:56

I am always amazed by the convergence of the mechanical and electrical units, with one Joule equalling one Watt second.
The choice of the units of length, mass, and time are what might be called natural units that were chosen with no regard to electrical units that makes the convergence all the more surprising.
I believe that the Amp is defined as by the magnetic force between current carrying parallel conductors, this leaves the Volt as the last unit that can be adjusted to make everything converge and by a happy coincidence it is approximately that of a common form of battery.
The units that stick out like a sore thumb are the Joule and the Calorie, this could be adjusted by making the Kelvin smaller by a factor of 4.18 which would make the triple point of water about 1140°K but no doubt we would get used to it much as we have managed the transition from Farenheight to Centigrade

syhprum

Title: Re: SI units
Post by: daveshorts on 23/10/2006 12:57:47

It certainly isn't serendipady, the size of the Volt was chosen as 1J/s/A .

The Calorie isn't an SI unit, so why is it relevant?