M R wrote:
>
> Metric System tries to be as precise as possible.
> Earlier we said that 0 degrees centigrade = 273 K,
> now we say that 0 degrees celsius = 273.15 K and
> tomorrow an even precise unit will declare
> 0 degrees at 273.15323432 K.
There is absolutely nothing that will cause the definition of "0
degrees [Celsius] at 273.15323432 K", Madan. This is not a relationship
based on experimental observation, where improvement in precision will
add digits to the right. It is an absolute value by definition. That is,
the temperature of water at the triple point has a temperature of, by
definition,
273.160 000 000 000 000 ... K
or
0.010 000 000 000 000 ... �C.
> For a layman its enough if we say that
> 0 degrees celsius = 273 K and the decimals matter only
> for a person studying/working with science.
Certainly, if one wished to convert a statement such as "the Sun's
apparent surface temperature is 5800 K" to Celsius, one would not add
the extra 0.15 degrees Celsius to the result. In fact, one would
probably add just 300 and be done with it, saying "the Sun's apparent
surface temperature is 6100 �C".
> In the same way, 1 day contains 86,400 seconds and
> earth's circumference is 40,000 km. So milliseconds
> and decimal part of km are not relevant for a common
> man unless they ask for it.
I agree. It is the uncommon man, woman, or application where this is
important.
> Lets talk at integer level for a layman and decimal
> level for a scientist or research guy.
Agreed, but let's take care not to misrepresent the definitions. Call
approximations what they are. To say that the length of the day is
defined in SI by the period of Earth's rotation is wrong. That's only a
very, very close approximation. It's a bit like saying a liter of water
weighs a kilogram. That's an approximation that I use quite often and
even pass to others -- as an approximation.
Jim
--
Metric Methods(SM) "Don't be late to metricate!"
James R. Frysinger, CAMS http://www.metricmethods.com/
10 Captiva Row e-mail: [EMAIL PROTECTED]
Charleston, SC 29407 phone/FAX: 843.225.6789
