Differences

This shows you the differences between the selected revision and the current version of the page.

activities:guides:vfvring 2012/08/02 12:56 activities:guides:vfvring 2013/10/02 11:02 current
Line 75: Line 75:
  * The final component is that students need to recognize an elliptic integral and what to do when they run into one. Most commonly students have never seen such `unsolvable' integrals in their calculus classes. In our case we had students do the power series expansion before the integral (see below).   * The final component is that students need to recognize an elliptic integral and what to do when they run into one. Most commonly students have never seen such `unsolvable' integrals in their calculus classes. In our case we had students do the power series expansion before the integral (see below).
 +
Line 85: Line 86:
  * With the charged ring in the $x,y-$plane, students will make the power series expansion for either near or far from the plane on the $z$ axis or near or far from the $z$ axis in the $x,y-$plane. Once all students have made significant progress toward finding the integral from part I, and some students have successfully determined it, then the instructor can quickly have a whole class discussion emphasizing some of the points above, followed by telling students to now create a power series expansion. The instructor may choose to have the whole class do one particular case or have different groups do different cases.   * With the charged ring in the $x,y-$plane, students will make the power series expansion for either near or far from the plane on the $z$ axis or near or far from the $z$ axis in the $x,y-$plane. Once all students have made significant progress toward finding the integral from part I, and some students have successfully determined it, then the instructor can quickly have a whole class discussion emphasizing some of the points above, followed by telling students to now create a power series expansion. The instructor may choose to have the whole class do one particular case or have different groups do different cases.
-  * If you are doing this activity without having had students first create power series expansions for the electrostatic potential due to two charges, students will probably find this portion of the activity very challenging. If they have already done the <html><a href="http://www.physics.oregonstate.edu/portfolioswiki/doku.php?id=activities:main&file=vfvpoints">Electrostatic potential due to two points</a></html> activity, or similar activity, students will probably be successful with the $y$ axis case without a lot of assistance because it is very similar to the $y$ axis case for the two $+Q$ point charges. However, the $y$ axis presents a new challenges because the ``something small'' is two terms. It will probably not be obvious for students to let $\epsilon = {2R\over r}\cos\phi' + {R^2 \over r^2}$ (see Eq. 17 in the solutions) and suggestions should be given to avoid having them stuck for a long period of time. Once this has been done, students may also have trouble combining terms of the same order. For example the $\epsilon^2$ term results in a third and forth order term in the expansion and students may not realize that to get a valid third order expansion they need to calculate the $\epsilon^3$ term.+  * If you are doing this activity without having had students first create power series expansions for the electrostatic potential due to two charges, students will probably find this portion of the activity very challenging. If they have already done the <html><a href="http://www.physics.oregonstate.edu/portfolioswiki/doku.php?id=activities:main&file=vfvpoints">Electrostatic potential due to two points</a></html> activity, or similar activity, students will probably be successful with the $z$ axis case without a lot of assistance because it is very similar to the $y$ axis case for the two $+Q$ point charges. However, the $y$ axis presents a new challenges because the ``something small'' is two terms. It will probably not be obvious for students to let $\epsilon = {2R\over r}\cos\phi' + {R^2 \over r^2}$ (see Eq. 17 in the solutions) and suggestions should be given to avoid having them stuck for a long period of time. Once this has been done, students may also have trouble combining terms of the same order. For example the $\epsilon^2$ term results in a third and forth order term in the expansion and students may not realize that to get a valid third order expansion they need to calculate the $\epsilon^3$ term.

Personal Tools