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====== Potential Due to Point Charges ======

{{page>courses:prereq20:sypre:sypresuperposition}} FIXME - links
  * Reading: GVC (ss) [[bb>book:physics:superposition|Superposition]],[[bb>book:physics:drawquadrupole|Visualization of Potentials]]--[[bb>book:physics:drawquadrupolehint|More Visualization of Potentials]],[[bb>book:physics:visv|Using Technology to Visualize Potentials]]--[[bb>book:physics:visvhint|More Using Technology to Visualize Potentials]]

===== In-class Content =====

  * Refresher 2 (15 min)
  * Equipotentials Activity (85 min)
    * Lecture before the activity:
      - SWBQ: Write down something you remember about //superposition//.
      - How would you use superposition to find the gravitational potential halfway between the Earth and the Moon?
      - Both electrostatic potentials and gravitational potentials satisfy the superposition principle.  It would have been very difficult for us ever to have developed the field of physics if this were not the case.
    * Draw equipotential lines for a configuration of four positive point charges arranged in a square.
      * Whiteboards should be prepared with four points with the correct spacing.
      * Students may not know what an "equipotential" is or what it means.
      * Let the instructors do as much direct talking with the groups as possible before whole-class discussion.
    * Whole-class discussion (middle of activity):
      - Make sure you pay attention to how far apart your equipotential lines are.
      - What do the equipotential surfaces look like for a point charge?
        * Are the proper equipotential surfaces two-dimensional or three-dimensional?
      - How do you represent equipotential lines with //different// values?
    * Let students go again until most have good answers, then bring back together for wrap-up of the correct solution plus introduction to Mathematica.
    * Draw equipotential lines for a quadrupole.
      * Warn students not to erase the dots.
      * Hand out the surface at the start of the activity.  (Students won't know that they are dry-erasable!)
      * Tell students they can modify the Mathematica worksheet to show this charge configuration.
    * Whole-class wrap-up (end of activity):
      - What do you want to remember about this problem for future problems?
      - What is the meaning of the spacing between equipotential lines?
      - What was different about the two charge configurations we did?
      - What did Mathematica help you with?
      - What did the plastic surface help you with?
      - Submit a reflection on Canvas!

===== Original in-class content =====
  * Equipotentials Activities
    * [[..:..:lecture:sylec:superposition|Superposition]] (Lecture: 35 min)
    * [[..:..:activities:vfact:vfdrawquadrupole|Drawing Equipotential Surfaces Due to a Quadrupole]] (SGA: 45 min)
    * [[..:..:activities:vfact:vfvisv|Visualizing Electrostatic Potentials]] (Maple/Mathematica: 20 min)  
  * [[http://phet.colorado.edu/sims/charges-and-fields/charges-and-fields_en.html|Play with the PHET simulation]]


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