Teaching SI Units in Engineering and Technology Programes

As technology and economy gain global integration, the use of SI units (Systeme Internationale d’Unites) has become common place. About 95% of the world population is familiar with the system with a vast majority using it as the primary units of measure. In fact, the only countries today that are not fully metricated are United States, Liberia, Myanmar (formerly Burma), and Brunei. So the English units are still the popular units in the United States and it is the preferred units of instruction in our colleges and universities, especially in engineering and technology programs. This paper discusses an approach in teaching SI units in engineering and technology programs. The approach is based on a M20-50 strategy for Junior Colleges in technical and vocational education. The prefix “M” stands for Metric and the numbers 20 and 50 represent the minimum percentage Metric content in assignments for first-year and second year-students, respectively. A M20-40-60-80 strategy is used for 4-year colleges and universities in engineering, engineering technology, and technical education. This requires that the assignments for students should have 20%, 40%, 60%, and 80% minimum metric content for first-, second-, third-, and forth-year students. From our experience, most of the students claim it is easier and faster calculating in Metric units than English. They think fewer mistakes are made in metric calculations compared to English; especially when working with fractions in English units. We have found that many industrial and engineering technology students are not well grounded in the units of fundamental quantities like area, volume, pressure, stress, flow rates, etc. Though they talk about these quantities regularly, they fail to capture their proper units. Hence teaching units, in general and SI units in particular, is imperative not just for metrication purposes but also for sound education. P ge 23148.2 Introduction A unit of measurement is a standard for measuring a physical quantity that may be defined through voluntary agreement, adopted by convention or defined by law. Measurement units and standards are developed and managed by professional organizations (e.g. ASME: American Society of Mechanical Engineers, ASTM: American Society for Testing Metals, ASQ: American Society for Quality, IEEE: Institute of Electrical and Electronic Engineers, SAE: Society of Automotive Engineers, etc.); national and international bodies such as the American National Standards Institute (ANSI) and International Standardization Organization (ISO). The ISO develops and manages SI units and standards. The metric system is defined as the current version of SI units and standards. ANSI coordinates the adoption and management of United States National Standards. The United States is the only industrialized nation where English or United States Customary units are in common usage though English units have been defined using metric standards since 1893 [1] . A system of units is a group of fundamental units and their combinations that constitute a language of measurement. The magnitude of a physical quantity is completely specified by a number and a unit. The number gives the size of the quantity while the unit identifies the type of quantity. The unit gives the number a context so that it can be properly understood and interpreted. Lord Kelvin in 1883; captured the importance of measurement units when he said “...when you can measure what you are speaking about and express it in numbers, then you know something of your subject; when you cannot express it in numbers, your knowledge is of a meager and unsatisfactory kind” [2, 3] . Unit systems can be divided into two groups; namely base units and derived units. Base units are standardized with respect to fundamental physical quantities, the choice being somewhat arbitrary. They measure basic physical quantities such as length, mass and time. Derived units are obtained by combining two or more base units. Many derived units can be expressed in more than one form but it is professional to adhere to conventions, especially standards. In the United States, the SI and English units and standards are in use. The SI Units is as a result of 17 th and 18 th centuries’ proposals for a uniform standard of units. This standard is continuously being revised and the United States has been participating since 1875. The metric P ge 23148.3 system was first suggested by Simon Stevin in 1585 but was adopted in 1790 by the French Academy of Sciences which started to develop it into a practical system. Thomas Jefferson recommended the use of the metric system in 1790, but in hindsight, his advice appears not to have been taken seriously. In 1795, France officially adopted the metric system and by 1900, 35 more countries had adopted it. In 1866, by an Act of Congress, the metric system became lawful throughout the United States in all contracts, dealings and court proceedings. After many decades of debates, Congress passed the Metric Conversion Act (P. L. 94-168) in 1975 [1, 4] . This Act made the metric system the legal units of weights and measures in the United States, but actual adoption by business and public has been somewhat slow. SI units and standards are the most widely used measurement units system today. About 95% of the world population is familiar with the system with a vast majority using it as the primary units of measure. The United States customary units have their roots in the English System which developed from the system used by early American Colonists. Several versions of the units are in use but the popular ones are the foot-pound-second (fps) system and the inch-pound-second (ips) system. United States customary or English units are managed by the National Institute of Standards and Technology (NIST). In English units, some quantities have multiple unit variants that seem unrelated. For instance, energy can be measured in BTUs (British Thermal Units), foot-pounds, kWh (kilowatt hours), kilotons (explosive energy), etc. Also, the English units system has many conversion factors, making them more complicated to remember. For example, there are 8 ounces in a cup, 2 cups in a pint, 12 inches in a foot, 3 feet in a yard, and 5280 feet in a mile. The growth of worldwide science and commerce has greatly accelerated the adoption of SI units of measurement throughout the world so that the metric system, (the current version of SI units and standards), is now the world's measurement language for trade and science. Therefore, it has become necessary for technicians, technologists, designers, and engineers in the United States to become competent in the metric system. Since the global economy is here to stay and metric is the international language, it seems obvious that full conversion to SI units is a matter of time! Full conversion to metric system will ensure that the United States stays at the leading edge in scientific and technological innovation. P ge 23148.4 In the United States’ academia, the SI units and standards are popular in the scientific community while the English units and standards are popular in the engineering and technological communities. Because English units system is used in training the vast majority of our engineers, technologists, and technicians, they are probably ill equipped for the global stage where the SI units system is the measurement language of trade and science. For instance, when companies from different countries work on the same technical project(s), the use of a common unit of measure is necessary. Since the SI units system is international, this is often the preferred choice. According to Euler [5] , all new USA standards (ASTM, ANSI, SAE, IEEE, ASME, etc.) are now written in metric. This is because, the lead engineers in these organizations recognize the importance of trying to get the USA on track with technically advanced countries, in an effort to regain lost USA competitiveness in a global economy. The global market for English unit products is continuously shrinking and American industries using them forfeit industries and jobs to third-world countries that use the simple SI units and fulfill business needs efficiently. If our engineering and technology graduates are to lead the global technological enterprise, they must be highly competent in the use of the SI Units system. In addition, engineering and technology degree graduates competent in SI and Metric units would have greater employment opportunities as expertrates in other countries. The rise of China, India, and Brazil as technological powers will further increase the need for our graduates in technology and engineering to be more competent in the use of SI units and standards. Training our students for competence in the job market is important to all of us. In fact, job placement rate is one of the assessment criteria of various Accreditation bodies of programs. SI literacy and competence are factors that will be relevant in getting employed in a global economy which can influence placement rates. This paper discusses strategies for accelerating the training of engineering and technology students in the use of the SI units system in post-secondary technical education system. This will eventually help in metricating the whole economy due the predominance of graduates literate and competent in SI usage. A M20-50 strategy is proposed for junior colleges in technical and vocational education system. The prefix “M” stands for “metric” and the numbers 20 and 50 represent minimum percentage metric content in assignments for first-year and second yearstudents, respectively. A M20-40-60-80 strategy is proposed for 4-year colleges and universities in engineering, engineering technology, and technical education. This requires that the P ge 23148.5 assignments for students should have 20%, 40%, 60%, and 80% minimum metric content for first-, second-, third-, and forth-year students. It is hoped that