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Viewing Message ``Re: Lorentz Force Law'' by wmccutchen on 2008-09-09 14:01:34 Wikipedia, as well as PlanetPhysics, has a hyperlink approach, but many articles are obscure because of the assumptions regarding the education of the reader.  Formulas, especially, are a turn-off to beginners, especially when they don't know what the letters stand for.  PlanetPhysics might make it a policy to hyperlink every variable in a formula, and in units of measurement. The Lorentz Force explains how a disk dynamo (Faraday disk) works: moving a charge (by turning the disk where the charge resides) through an axial magnetic field produces a radial current.  Positive charges drift radially one way, and negative charges (electrons) go opposite.  The direction of rotation and the direction of the axial magnetic field determine which radial direction the charges migrate.  These interesting devices produce huge currents and are used for welding and for rail guns, so they should provide a gateway to discussion of the Lorentz Force Law.  Faraday made the first generator this way.  Unfortunately, confusion over "conventional current" vs. electron flow, and right-hand or left-hand rules, and "electromotive force" and "potential difference" make it hard to figure out where the electrons go. Experts, as you point out, disdain to explain these stumbling blocks to understanding.  Part of the hazing process, maybe, that every student must go through.  I disagree with that view.  I just wanted to say ouch so you would pay some attention to this difficulty, which I am happy to see you have.  Good luck and kudos for your worthy cause.   [ reply | up | top ] Interact reply

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