engleski

Using analogy in developing students' conceptual understanding of electrical properties of matter

Teaching by analogy is not yet sufficiently used within our practice. This could be partially because of the fear of introducing additional misconceptions to students but also because the teacher could be "accused" of trivializing the important physical concepts. Physics, especially quantum mechanics, mostly relying on an abstract language of mathematics, as such remains difficult to understand or unclear. We are aware that our comprehension of physical phenomena comes from the world accessible to our senses. This is a world of interaction and motion - the world of classical mechanics. Through the use of analogy of our macro world to describe the micro world and noticing similarities among seemingly different processes at different spatial and temporal scales, we set a natural way of thinking, teaching and learning. Analogy, although not completely accurate, can help us to perceive, model and predict the behavior of systems that are invisible to the human eye. This can be illustrated by the examples from history. It is well known that thermodynamics have been developed on the incorrect assumption that heat is a kind of fluid. Regardless of such an assumption, Carnot derived the correct expression for the maximum possible efficiency for any heat- engine. Likewise, although Tesla did not fully master the language of mathematics, his notion of electricity as a fluid enabled him to "see" and to perceive things invisible to the human eye and led him to important discoveries. In fact, it is worth asking is it even possible to understand the world without analogue ideas? The goal of the talk is to discuss the analogies that describe the separation and transport of charge carriers in different materials. The original model of electricity based on the analogy with cars and highway traffic will be introduced. It will be shown that the model easily introduces quantum mechanical description of the electronic bands in solids with both electrons and holes as charge carriers. Note that quantum-mechanical description is necessary for proper understanding of conductivity in metals, semiconductors and insulators as well as operating principles of devices such as transistors, photocells and thermoelectrics.

teaching by analogy, electrical conductivity, misconceptions

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