Move compass to see field lines
http://www.walter-fendt.de/html5/phen/magneticfieldbar_en.htm
Move compass to see field lines
http://www.walter-fendt.de/html5/phen/magneticfieldbar_en.htm
Move compass to see field lines, see strength of field
http://www.physicsclassroom.com/Physics-Interactives/Magnetism
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