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Particle reasoning surge?

  1. Oct 12, 2014 #1


    Staff: Mentor

    I have noticed a surge in questions in the physics forums from people tying themselves up in knots trying to understand fields, electrical and electronic devices, and especially Ohm's Law, by reasoning one electron at a time. They get themselves tied up in chicken-egg issues and circular definition loops. IMHO their struggles are needless and caused by attempts to understand things at an overly fundamental level.

    Ohm's Law V=IR, is a very simple and incredibly useful. But that is a bulk (averaged) form of the law. Ohms Law can also be expressed in terms of fields distributed in time and space, but only after the student has sufficient calculus to accurately describe it. I do not believe that attempts to understand the distributed form by intuition alone is fruitful. One can study how to make use of resistors without learning how resistance arises on the molecular level. Students who have not yet learned the math should IMHO be encouraged to explore V=IR in all it's glory while never trying to visualize it one or two electrons at a time.

    The same applies to magnetic fields, generators, motors and the electric grid. It is not fruitful to study those without calculus and differential equations.

    The same applies to particle mechanics. Temperature is a 3D scalar field that at the particle level expresses kinetic energy. Wind is a 3D vector field that at the particle level expresses kinetic energy. If one starts visualizing one particle at a time, he/she might come to the absurd conclusion that temperature and wind must be the same thing. Without calculus, these topics should be studied only at the bulk level, forgetting particles.

    Perhaps the surge in such questions is in my imagination. I have not done statistical analysis. But perhaps it results from a change in elementary/secondary science education methods that believe that science is most easily understood at the fundamental level and working up. Is that the case?
  2. jcsd
  3. Oct 17, 2014 #2
    Thanks for the post! Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?
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