Hi samhain

http://physics.nist.gov/cuu/Units/index.html

a good website for explaining the System International SI or the Le Système international d'unités. (you can blame those French and Scottish Physicists I'm afraid)


The Celcuis temperature isn't strictly within the SI fundemental units but is derived from them. Thermodynamic temperature is measured in degrees Kelvin (K).

length meter = m
mass kilogram = kg
time second = s
electric current ampere = A
thermodynamic temperature = Kelvin K
amount of substance mole = mol
luminous intensity candela = cd

So from just these basic units of fundemental measurement even he mostcomplex physical measurement quantities such as electromagnetic inductance or thermal conductivity can be derived.

The problem with working with imperial measurements is that they soon become difficult to use when describing complex physical measurements. Fahrenheit temperature scale for example isn't related to any physical quantity and is almost arbitrary. The one description I like the best to describe how the scale works is;

'A seventh version maintains that the coldest temperature he could achieve in the lab was designated with 0 degrees, and the melting point of butter was 100 degrees'



well this is easy the answer is 2' 11 15/16", its just that most folks have forgotten how to do fractional arithmetic because of the use of calculators. But then again most people don't know how many rods are in a furlong or how many pecks are in a bushel. Making measurements of physical quantities such as electromagnetic inductance using imperial measurements soon turns into a nightmare.

14.6cm = 146mm is spot on BTW.



This ban isn't going to happen anytime soon in the UK for reasons of national politics I'm afraid.