Electricity can be thought of as a ubiquitous and ultimate black box system: although many people have a fairly good understanding of what goes in (combustion of fossil fuel in a large thermal plant; falling water in a hydro station; solar radiation absorbed by a photovoltaic cell; the splitting of uranium in a reactor) and everybody benefits from what comes out (light, heat, motion), only a minority fully understand what goes on inside the generating plants, transformers, transmission lines, and final-use devices.
