Interactive Learning Engines for Fundamental ElectromagneticsRobert Lord
Department of Communication and Electronic Engineering, RMIT University
So you think you know what electricity is?
If you are like most year 2 students at RMIT you probably believe the "water analogy" model of electricity so I want to put that model to the test now. Consider the simple circuit shown in Figure 1.
Figure 1. Simple electric circuit
Do you expect the voltage and currents to be as given in Figure 2? The circuit is open at the right hand end so no current can flow allowing the voltage to be 10 volts at each end of the circuit immediately after the switch is closed.
Figure 2. Water analogy predictions
Real world laboratory measurement however, Figure 3, gives results which are very different to these predictions. This is the problem when teaching the fundamentals of electromagnetics to year 2 students at RMIT Communication and Electronic Engineering. A new model for electricity is needed to predict the real world measured results obtained in the laboratory.
Figure 3. Real world measurements
The water analogy ignores the large but finite speed of electrical energy propagation. For many high speed computer circuits of today and all high speed computer circuits in 5 to 10 years time this finite speed of electricity will not be able to be ignored. The information superhighway and mobile phone industry already takes this finite speed of energy propagation into account by using what is called distributed circuit theory to suitably enhance traditional lumped circuit theory to take into account the energy speed.
The flexible modules that form the introductory course in electromagnetics have the central aim of changing the learners' belief system about "what electricity is". This is a very demanding challenge and has motivated the pedagogy of the modules.
Learning engines have been developed to enable students to build up Personal Practice Knowledge (PPK) by making many measurements and observations using the learning engines, Figure 4.
The major purpose of these measurements and observations is to change the learner's belief system1 and so connect the new "updated" model of electricity into that belief system.
Figure 4. Learning engine
A Virtual Learning Engine, Figure 5, has been developed to enable students to begin to build PPK2 before using the limited number of expensive real learning engines in the laboratories. Virtual Learning Engines are useful but seem not to convince students of the validity of the cognitive conflict anymore than being told by the lecturer.
Figure 5. Virtual Learning Engine
The real learning engine measurements and observations are grounded in an undeniable reality and slowly but surely students come to see the limitations of the water analogy. Once they come out of the 'PIT' of the Transformational Learning Curve3,4, Figure 6, and are on the steep rise of that curve, the Virtual Learning Engine simulation provides a convenient test bed for their new understanding.
The model of learning5 underlying the modules is about establishing the learners' current understanding, setting up a cognitive conflict, and providing student centred activities to allow the learners to resolve the conflict and come to a new understanding.
Figure 6. Transformational Learning Curve
The pedagogy has worked well for most of the students but it seems that some have a predisposition to react rather than act, respond rather that initiate, or be passive rather than active. Such students may excel under traditional university instruction but have some difficulty learning from student centred exercises designed for learners acting as researchers/discoverers. Experience using three flexible learning modules in introductory electromagnetics has indicated that a substantial minority of the students became overwhelmed because they were not well prepared for the researcher/discoverer role anticipated by the pedagogy underlying the modules.
UniServe Science News Volume 14 November 1999
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