Day 84: Earth’s Magnetic Field

I ended class yesterday by inducing cognitive dissonance after asking in what direction a compass needle points, which pole is the colored end of the compass needle, and how magnetic poles interact with each other. I let them ponder the implications of those answers overnight. I started class today with the MinutePhysics video about the North Pole:

Once students are amazed at behavior of the various north poles of the Earth, we discuss how the magnetic poles have swapped over the course of the Earth’s history. I share this simulation image from NASA that shows what the Earth’s magnetic field normally looks like and may look like during a pole reversal:



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