Rádio de Galena: das linhas invisíveis de Faraday às ondas eletromagnéticas

Abstract

We live in a period of great technological leaps, for example, in the last decades the advances in cell phone technologies are remarkable, but the understanding of electromagnetic waves used in these technologies is mostly restricted to specialized centers and research groups around the world. Thus, several fundamental concepts of physics are far from their technological applications within classrooms. In this context, the present work seeks to present, in a didactic way, the research carried out by Michael Faraday on electricity and magnetism in the 19th century. For this purpose, we are going to study and build the electronic components that are part of a radio of galena, which works without power supply from batteries or electrical network, but with the electromagnetic waves coming from an AM radio station (amplitude modulated) and that is picked up by a conducting wire. Therefore, we will carry out the construction of the components, assemble the galena radio and present all the work relating it to the theme of electromagnetic waves. In this way, we will demonstrate that the Galena radio is a clear example of the technological application of the themes of electricity and magnetism, being a structuring theme to be used as a didactic tool for teaching physics.