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Comment: 13:54 - 14:36 (00:42)
Source: Annenberg/CPB Resources - Earth Revealed - 5. The Birth of a Theory
Keywords: "Scott Bogue", paleomagnetism, "magnetic field", polarity
Our transcription: While the term "paleomagnetism" refers to ancient magnetic fields of the Earth, we can learn about, and we can say something about ancient magnetic fields of the Earth because of the record they leave in rocks.
If many rocks become magnetized when they are formed or some time after they are formed, when they become magnetized, they become magnetized parallel to the Earth's magnetic field at that time.
So if you can collect a rock sample, measure which way it's magnetized, and determine when it was magnetized, then you can learn about the orientation of the magnetic field at that time in the past.
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