Have you ever looked at the Wikipedia definition for a tesla? I like to start the unit by looking at it- discussing the importance of scale and the range of the strength of magnetism. I also like putting the definition of magnetism into the various contexts provided by the units- in terms of current, moving charges, or flux.
Introductory Demonstration
Stations
While a pain to set up, these experiences provide an intuitive understanding of the connection between electricity and magnetism- I can refer back to them at many points throughout the unit. Half of the stations are focused solely on magnetism; while the other half connect electricity and magnetism through movement- a connection I hope the students make!
While there is not that much content in this lecture to actually practice, this introductory provides the vocabulary- the units and models we use to talk about magnetism, as well as what causes it and gives and introduction to the magnetic force.
There are quite a few equations to keep constant here- and not to mention the right hand rules. Students get anxious about the RHR- i like to interrupt the lecture with some Plickers or other practice using the RHR to predict direction of the force.
Before this lecture, I do a simple ‘minilab’ on electromagnetic induction. For this lab, I assign each group a variable- speed, magnetic field strength, diameter of coils, etc. to vary as they drop magnets through coils of wire around PVC pipe and measure the maximum voltage produced using Vernier sensors. Multimeters do work, but due to the sampling rate I recommend doing LOTs of trials if using multimeters!
The lecture focuses on the math of it!