Ampegravere's motor: Its history and the controversies surrounding its working mechanism

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)In 1822 Ampere created a new kind of motor when he succeeded in spinning a cylindrical magnet around its axis by connecting it to a battery generating a steady current. Nowadays, it is easy to present such a motor in the classroom utilizing a neodymium magnet, a D battery, a steel nail, and a short piece of copper wire. Although it is very simple to observe the rotation, the explanation of this effect is still under dispute. This work presents the history of this motor including the controversy between Ampere and Faraday, as well as the modern explanation based on the field concept. We emphasize the positive outcomes to be gained in the classroom by presenting this device to students. (C) 2012 American Association of Physics Teachers. [http://dx.doi.org/10.1119/1.4746698]8011990995Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Organizing Committee of the First Latin American Conference of the International History, Philosophy, and Science Teaching GroupFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP