In order to understand and operate an engine efficiently it is necessary for the operator to be familiar with various units of measurement and the instruments by which they are recorded | 2 MEASUREMENTS AND INSTRUMENTS A. MEASUREMENTS 2A1. Fundamental and standard units. In order to understand and operate an engine efficiently it is necessary for the operator to be familiar with various units of measurement and the instruments by which they are recorded. As soon as any branch of science is developed to any extent attempts are made to measure and evaluate the quantities and conditions found to exist. To do this a unit must be selected for each measurable quantity. These units are derived from a set of basic units known as fundamental units. The fundamental units are units of force length and time. Fundamental units should not be confused with standard units. Standard units of measurement are units that are established and legalized by the government of a country. Whenever standardized units are established the fundamental units are expressed in terms of the standard units to secure uniformity of procedure and comparison. 2A2. The metric system of measurement. The metric system of measurement is used generally throughout the world particularly in Europe. It is not in general use in the United States. Because the metric system is a decimal system it is less subject to arithmetical error than the other common system the English system of measurement. Since the metric system uses the simple multiplier 10 it is easy to establish the value of the unit of measure as denoted by the prefix in the name of the unit. The table below explains how the prefix denotes the value of the unit of measure and gives examples of the use of the prefix. Prefix micro meaning Example micron Such units as length volume and mass are easily converted to the next higher denomination by using the simple multiplier 10. For example Units of Length 10 millimeters 1 centimeter 10 centimeters 1 decimeter 10 decimeters 1 meter 1000 meters 1 kilometer Units of Weight 10 milligrams 1 centigram 10 centigrams 1 decigram 10 decigrams 1 gram 1000 grams 1 kilogram 1000 kilograms 1 metric ton .
