TABLE OF CONTENTS The measurement and control of physical properties require the use of well-defined units. Units commonly used today are defined in either the English system or the Syst me International d'Unit s (SI) system [1]. The advent of the Industrial Revolution, developing first in England in the eighteenth century, showed how necessary it was to have a standardized system of measurements. Consequently, a system of measurement units was developed. Although not ideal, the English system (and U.S. variants; see gallon and ton) of measurements became the accepted standard for many years. This system of measurements has slowly been eroded by the development of more acceptable scientific units developed in the SI system. However, it should be understood that the base unit dimensions in the English or SI system are artificial quantities. For example, the units of distance (e.g., feet, meter), time, and mass, and the use of water to define volume, were chosen by the scientific community solely as reference points for standardization.
As with all disciplines' sets of units and standards have evolved over the years to ensure consistency and avoid confusion. The units of measurement fall into two distinct systems: the English system and the SI system [2].
The SI units are sometimes referred to as the centimeter-gram-second (CGS) units and are based on the metric system but it should be noted that not all of the metric units are used. The SI system of units is maintained by the Conf rence Gen rale des...
