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Bar Magnet and Compass Interactive

The black rectangle represents a bar magnet. The magnet's North and South poles are labeled. The other item represents a compass; the red end of the needle is the end that would point towards Earth's North Magnetic Pole. Notice that the red end of the compass needle points toward the south pole of the magnet. For historical reasons, what we call "Earth's North Magnetic Pole" is actually the south pole of Earth's magnetic field! Yikes!

Drag either the compass or the magnet around to explore the magnetic field around the bar magnet. Can you determine the shape of the magnetic field?

(Note: If you cannot see the animation below, or it is not working properly, you may need to download the latest Flash player.)

This is an early draft version of this activity. We expect to replace it with a better version soon. Some things to be aware of:

  • If you drag either the compass or the magnet off screen and let go, you won't have any way to get them back. Reload/refresh the web page to start over.
  • The behavior of the compass might be a bit different in the real world when you place it on top of the magnet.
Last modified August 22, 2007 by Randy Russell.

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA