Today in class:
-went over exam and copied down questions/answers to study for cumulative exam
-Magnetism pre-assessment (5 questions, not for points)
-Worked with compasses - compasses are small magnets that are free to rotate; they line up with external magnetic fields. Typically this is the Earth's field. We all know that opposite poles attract and like poles repel from elementary Science, so what does this mean about the Earth's magnetic field? If the compass's north pole points northward, then its south pole points southward... This means that its north is attracted to North on the Earth!!???!!?? Well, yes. Earth's Geographic North pole is actually its South Magnetic pole. (it's off by a bit, but it's in Canada) Our South Geographic is, you guessed it, North Magnetic.
So Santa Claus actually lives at the South Magnetic pole. Who knew?
-Magnetic materials (preview) - looked at wire (copper) vs. alligator clips (steel) and saw that copper did not affect compass, but steel did. More on this later.
-Magnetic field in current carrying wire - we experimented with current in a wire that's held near a compass - we were able to see that the needle deflected different amounts depending on the amount of current and its orientation relative to the compass, then we tried reversing the direction of current and found that the compass needle moved the other direction. We'll learn how to predict this tomorrow.
Tonight's homework: READ p. 424-430
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