by Nikolai Shokhirev

Prof. F. Ann Walker Research Group, Department of Chemistry, University of Arizona, Tucson, Arizona 85721, USA

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Introduction

This page was originally developed as reference data for Dr. Walker Research Group.

The large variety of the units of measures used in different areas and in different times causes a great deal of confusion. Obviously any particular set of units can be recalculated to another. This can be done if we have well-defined standard units and reliable conversion factors. Below we use the SI system of units as a standard. Note that the SI units are not necessarily the most convenient in some specific areas.

SI units

For basic definition and details visit the site A Dictionary of Units of Measurement by Russ Rowlett: http://www.unc.edu/~rowlett/units/index.html  and National Institute of Standards and Technology http://physics.nist.gov/ 

Base quantity	Symbol	Name	Unit
Basic units
Length	L	meter	m
Mass	M	kilogram	kg
Time	T	second	s
Electric current	I	ampere	A
Thermodynamic temperature	K	kelvin	K
Amount of substance		mole	mol
Luminous intensity		candela	cd
Derived units
Frequency		hertz	Hz = s -1
Force	F	newton	N = m·kg·s -2
energy, work, quantity of heat	E	joule	J = N·m = m 2·kg·s -2
Power		watt	W = J/s = m 2·kg·s -3
Pressure	P	pascal	Pa = N/m 2 = m -1·kg·s -2
Electric charge, quantity of electricity	Q	coulomb	A s
Electric potential difference, electromotive force	V	volt	V = W/A = m 2·kg·s -3·A -1
Capacitance	C	farad	F = C / V = m -2·kg -1·s 4·A 2
Electric resistance		ohm	= V / A = m 2·kg·s -3·A -2
Electric conductance		siemens	S = A/V = m -2·kg -1·s 3·A 2
magnetic flux		weber	Wb = V·s = m 2·kg·s -2·A -1
magnetic flux density	B	tesla	T = Wb/m 2 = kg·s -2·A -1
Inductance		henry	H = Wb/A = m 2·kg·s -2·A -2

The basic physical interactions are presented in the next section.

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