8

CHAPTER

Magnetism

A MAGNETIC FIELD ARISES WHEN ELECTRIC CHARGE CARRIERS MOVE. CONVERSELY, WHEN AN ELECTRIcal conductor moves in a magnetic field, current flows in that conductor.

Geomagnetism

The earth has a core consisting largely of iron, heated to the extent that some of it liquefies. As the earth rotates on its axis, the iron in the core flows in convection patterns, generating the geomagnetic field that surrounds our planet and extends thousands of kilometers into space.

Earth’s Magnetic Poles and Axis

The geomagnetic field has poles, just as an old-fashioned bar magnet does. On the earth’s surface, these poles exist in the arctic and antarctic regions, but they are displaced considerably from the geographic poles (the points where the ...

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