Working Backwards Task - Faraday's Law

Activity Description

The animation shows a top view of four wires and a galvanometer in the lab. Current flowing into the + terminal, i.e., counterclockwise, will deflect the meter to the right. During the time interval t=2 s to t=8 s a magnet is slowly pushed completely through the rectangle from the bottom toward the top. (You can also think of the magnet as being pushed out of the computer monitor toward the user. Note: the magnet is not shown.) Students observe the meter reading during this simulation and then decide on which pole of the magnet passes through the pole first.

Target Conceptual Difficulty

Lenz's law gives that the direction of the induced emf opposes the change producing it.

PowerPoint

Working Backwards Task - Faraday's Law (TurningPoint Version)

Working Backwards Task - Faraday's Law (iClicker Version)

Simulation

Working Backwards Task - Faraday's Law

Presentation Notes

This simulation is not set up to demonstrate the correct answer, so correct answer will be given by instructor.

Student Results

This task proved to be a very difficult one for the students and in future use I plan to use several easier tasks prior to giving the students this one. Prior to small group discussion only 38% of the students correctly that the N pole of the magnet was inserted through the loop first. 

1.) Which pole of the magnet was put through the loop first?

Responses (percent) (count)

N 37.50% 9

S 41.67% 10

It cannot be determined 20.83% 5

Totals 100% 24

Following small group discussion students were swayed away from the correct answer with 50% identifying that the S pole was inserted through the loop first.

2.) Which pole of the magnet was put through the loop first?

Responses (percent) (count)

N 16.67% 4

S 50% 12

It cannot be determined 33.33% 8

Totals 100% 24

Pen and Paper Actvivities

Pen and Paper version of this activty

Follow up tipers from homework assignments, test reviews and test items

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Last Updated: May 23, 2011