SI units

SI units (Système international d'unités) are now the general fundamental units for scientific work. The main basic units with which you will be concerned are the meter (m), the gram (g) and the second (s). Other non-SI units, notably minute (min), hour (h), degree Celsius (°C) and litre (l) are still commonly used in science, and will be used in this manual frequently. When using abbreviations, never add the letter "s" in an attempt to signify plurals. Below are some of the common symbols:

Symbol	Prefix	Factor
c	centi	10-2
m	milli	10-3
μ	micro	10-6
n	nano	10-9
p	pico	10-12

(1 l = 10³ ml = 10⁶ μl, 1g = 10³ mg = 10⁶ μg)

The units of amount of substance, mole (mol), and concentration of substance molar (M) are also frequently used.