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USGS CMG InfoBank: Loadstones and Compasses


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Comment: 18:07 - 18:45 (00:38)

Source: Annenberg/CPB Resources - Earth Revealed - 3. Earth's Interior

Keywords: "James Sadd", magnetism, Greeks, navigation, compass, loadstone

Our transcription: Geophysicists continue to learn a great deal about the characteristics of the Earth's magnetic field and the processes that generate it.

But the magnetic field of the Earth has been observed for centuries, ever since the Greeks discovered lodestone, a natural magnet, some 25 hundred years ago.

Mariners discovered early on how useful this curious metal can be.

When a sliver of lodestone is placed on a piece of wood floating on water, it always turns to point approximately north.

The simple magnetic compass was to guide navigators to every corner of the globe.

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Accessibility FOIA Privacy Policies and Notices
U.S. Department of the Interior \| U.S. Geological Survey URL: http://walrus.wr.usgs.gov/infobank/programs/html/school/moviepage/03.01.25.html Page Contact: InfoBank staff Page Last Modified: Wed Aug 27 06:13:48 PDT 2008 (wcs)