Tutorial on Earth's Magentic Field (NASA) http://image.gsfc.nasa.gov/poetry/magnetism/magnetism.html Exploring Magnetism An Introduction to Geomagnetism An Introduction to Geomagnetism An Introduction to Geomagnetism http://image.gsfc.nasa.gov/poetry/magnetism/magnetism.html http://image.gsfc.nasa.gov/poetry/magnetism/magnetism.html http://image.gsfc.nasa.gov/poetry/magnetism/magnetism.html http://image.gsfc.nasa.gov/poetry/magnetism/magnetism.html An Introduction to Geomagnetism