ABSTRACT
Both electricity and light are mysterious. We are well aware of their effect, but, if asked the question “what is electricity?” or “what is light?”, we have difficulty giving a convincing answer. We find it easiest to think in terms of a model, or models, which make it possible for us to understand how an electrical or optical device works. Provided the model, or “mind picture”, is consistent, this is a quite acceptable way to proceed – indeed it is the only way for the layman to get an insight into physical processes. In this chapter we describe the simplest models of electricity and light to the point where the methods of controlling them can be understood.
