Traditional teaching of engineering fundamentals
In the teaching of engineering-related disciplines, the importance of understanding basic scientific principles cannot be overemphasised. Quite simply, the success of the whole enterprise depends on how well the fundamental principles are taught. A good teacher (in the context of engineering education) is one who teaches the fundamental concepts well—an art that requires considerable skill. It is not just a question of teaching methodology, but also one of wisdom and experience. The primary role of personal experience in the acquisition of knowledge has of course long been recognised1. A good lecturer is often someone who can draw on personal experience and teach in simple terms that students can relate to.
At present, most Engineering foundation courses in universities are organised and taught in a fairly impersonal way. Not only are the classes large, the course content is also usually presented in the form of technical diagrams and formulas without any reference to their historical context (e.g. When was a particular principle first discovered? Who discovered it? How did it come about? What were the problems that inspired it?). There is usually little in the lecture material that correlates directly with the students’ experience and practical applications of the principles are seldom mentioned. Even in tutorial classes, which are specifically designed for personal involvement, there is hardly any room for the students to be creative. Questions usually come with preset answers and student participation is limited to how they arrive at the predetermined answers.
Most Science and Engineering foundation courses at present require students to complete a certain number of laboratory exercises. Although these laboratory tasks are designed to provide students with some hands-on experience of the theoretical principles covered in lectures and tutorials, in reality the laboratory exercises give students very little opportunity to carry out genuine scientific investigation. This is because the laboratory experiments invariably consist of predefined tasks on set pieces of equipment. The apparatus often restricts students to merely pushing buttons and recording data, leaving little scope for students to innovate or experiment for themselves. Most Science and Engineering students at the foundation level therefore do not have the opportunity to practise science, and their knowledge of fundamental principles is largely theoretical. To be fair, NUS Engineering students do have more personal interaction with their lecturers in later years through project work. Though some engineering departments allow for project work in the foundation years, it is often limited by curriculum constraints.
The hands-on/historical approach
In the last few years, I have tried teaching engineering fundamentals using an alternative approach. A basic course on electricity and magnetism was designed to involve and engage the students personally. This course employs a hands-on/historical approach to teaching as opposed to one that relies only on formulas and technical diagrams. The basic scientific principles are introduced through historical stories. Lectures consist of case studies that attempt to put students in the frame of mind of the original inventor or discoverer. I give students a historical problem or episode and invite them to investigate it by asking, “what would you do?” I also continually compare students’ answers to what actually happened historically. Gradually, an interesting story which the students have actively participated in unfolds. At the end of the lecture, I perform several experiments using ordinary and readily available materials to re-create different aspects of the historical episode discussed. The students’ assignments require them to re-create the episode for themselves using their own materials. Specialised materials are given if required. Students typically have one to two weeks to do their own home experiments. They are told that their aim is to illustrate the underlying scientific principles involved creatively. They are free to re-create historical experiments or devise their own original experiments. During the tutorial, students would take turns to present their experiments which are graded by the other students and me.
The following is an example of how the hands-on approach can be used in the teaching of simple electrostatics. The usual traditional starting point in teaching electrostatics is to present a formula for Coulomb’s Law2, accompanied by a diagram of two charged spheres separated by a certain distance. There is usually some brief (one or two paragraphs) historical introduction. Students are then introduced to the concept of an electric field in mathematical terms, as the force per unit charge. The electric field is discussed as a Vector Quantity, and is calculated for simple charge distributions and conductor shapes. Thus, most students learn about electrostatics the theoretical way. Many have never experienced holding two charged spheres close together and even fewer have tried to measure electrostatic force or generate it for themselves.
An alternative introduction to electrostatics is to study a leaf electroscope3—one of the first instruments devised to measure electrostatic charge. During my lecture, students get to see how to create the instrument using simple materials. I would take a glass bottle with a plastic cap, secure a brass door-knob on top of the cap by making a small hole, and suspend two aluminium foil strips from a metal hook hung from the brass door-knob. Students also get to see it in action when I rub a PVC rod up and down with a woollen cloth and bring the rod close to the home-made electroscope, causing the aluminium strips to separate. It is a spectacular sight. Students can then go on to learn about Coulomb’s original torsion balance experiment and re-create it for themselves. Through carrying out such simple experiments by themselves, students can relate to the laws of electrostatics based on what they have experienced. When students are given opportunities to devise their own experiments using their own materials, it becomes a personal learning process. In this way, Coulomb becomes more than just the name of a ‘law’. Students can appreciate the 18th century French physicist’s contributions to electrostatics in a more meaningful way. All of these learning activities also enhance the students’ understanding of the basic scientific principles involved.
There are, of course, many more examples. The invention of the battery is a fascinating example that started historically with the twitching of a frog’s leg. The students discover that there are many home-made ways to create the ‘battery effect’ thus leading to a better understanding of the basic principles underlying electrochemistry. In all branches of Engineering, it is possible to recreate classic historical experiments using simple and readily available materials. It must be noted however, that the situation may be more complicated in other engineering subjects. In Chemical Engineering for instance, dangerous chemicals may be involved and these experiments may need to be done in a laboratory.
So far, I have used this hands-on/historical approach for classes of up to 30 students. In principle, it is possible to use this method for large classes although the degree of student participation will naturally decrease. However, demonstrations can still be presented to students after the lecture, so that students can tinker with the demonstrations for themselves. Moreover, home-made experiments can still be carried out as practical assignments and presented during tutorials. With the help of CDTL, I have created a website (see http://courses.nus.edu.sg/course/eleka/elecmagnet/) which contains some examples of demonstrations in electrostatics to promote the use of hands-on/historical approach in teaching engineering fundamentals.
1 Polanyi, M. (1958). Personal Knowledge. New York: Harper & Row.
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2 Hayt, W.H. Jr. (1989). ‘Coulomb’s Law and Electric Field Intensity’. Engineering Electromagnetics. 5th edition. New York: MacGrawHill. Chapter 2
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3 Keithley, Joseph F. (1999). The Story of Electrical and Magnetic Measurements: From 500 B.C. to the 1940s. New York: IEEE Press. p. 37.