SI units
SI units (Système international d'unités) are now the general fundamental units for scientific work. They are based on seven base units for seven base quantities which we assume to be mutually independent. The main basic units with which you will be concerned are the meter (m), the kilogram (kg) 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.
The Seven Base Units are as Follows:
| Base Quantity | Name | Symbol |
| Length | meter | m |
| Time | second | s |
| Mass | kilogram | kg |
| Amount of Substance | mole | mol |
| Thermodynamic Temperature | kelvin | K |
| Electric Current | ampere | A |
| Luminous Intensity | candela | cd |
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)