"A Novel Method of Teaching Dimensions, Units, Dimensional Homogeneity and Dimensional Analysis"

When most students are asked, "what are the primary units of the Systeme Internationale unitary system" (commonly referred to as the SI system of units, or the metric system), their first response usually is, "I was never taught that."Their second response is, "what is a primary unit?"And, their third response is, "how many of these primary units are there, anyway?"Unfortunately, these first responses are just as liable to come from fourth-year engineering students, as they are to come from first-year engineering students.All too often, these are the same first responses that are given by many Engineering educators, as well.And, since the incorrect use of Dimensions and Units contributes to such a high percentage of failures in the Engineering profession, it is also an indictment of the fundamental Dimensions and Units education in this country.Dimensional homogeneity, dimensional analysis and similitude are three of the most important fundamental design tools in engineering.Many introductory college classes in Engineering, and most introductory engineering textbooks, usually start off with a discussion on Dimensions and Units.But, that cursory review of dimensions and units in most first-year engineering courses is where most of the students' Dimensions and Units education stops.The lack of a proper knowledge of Dimensions and Units is one of the greatest contributors to catastrophic failure in scientific, industrial and manufacturing endeavors.And yet, only a casual introduction to dimensions and units is given to first-year engineering students, with the expectation that they will somehow eventually teach themselves the conceptual links and intricate interrelationships between the various engineering dimensions used in their discipline.This paper will examine case studies of how incorrect dimensions resulted in catastrophic failure, and will present a Primer on Dimensions and Units that can be used by Engineering Educators as a model to effectively give engineering students at any stage of their education a thorough introduction to Dimensions and Units, Dimensional Homogeneity and Dimensional Analysis.