The small-unit metric system (or more formally, the centimeter-gram-second (cgs) system of units ) is based on three fundamental units: the centimeter (cm), which quantifies displacement , the gram (g), which quantifies mass , and the second (s or sec), which quantifies time .
The small-unit metric system is so-called because one centimeter is equal to 0.01 meter (10 -2 m), and one gram is equal to 0.001 kilogram (10 -3 kg). The cgs system, like the metric system , was originally developed by scientists who were frustrated with the English (foot-pound-second) system. The cgs and metric system units of displacement and mass lend themselves neatly to calculations in scientific notation, while English units generally do not. Time remains somewhat messy in all systems; there are 60 seconds in a minute, 60 minutes in an hour, and 24 hours in a mean solar day.
The Standard International ( SI ) System of Units has officially supplanted the small-unit metric system (as well as the metric system). But it is good to have passing familiarity with the small-unit metric system, because that scheme is still used by some astronomers and physicists, and many older scientific books and papers were written with a preference for it. Today's SI System provides formal definitions for the meter , the kilogram , and the second , and also specifies and defines four additional units: the kelvin for temperature, the ampere for electric current, the candela for luminous intensity, and the mole for material quantity.