SUBJECT: A Bar Magnet in the Earth's Magnetic Field
DESCRIPTION: This model shows a bar magnet and compass sitting on a table in the TEAL classroom. The interaction between the magnetic field of the bar magnet and the magnetic field of the earth is illustrated by the fieldlines that extend out from the bar magnet. Fieldlines that emerge towards the edges of the magnet generally reconnect to the magnet near the opposite pole. However, fieldlines that emerge near the poles tend to wander off and reconnect to the magnetic field of the earth, which, in this case, is approximately a constant field coming at 60 degrees from the horizontal.
Looking at the compass, one can see that a compass needle will always align itself in the direction of the local field. In this case, the local field is dominated by the bar magnet.
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VISUALIZATION: Fullscreen Version