5G10.11 - Refrigerator Magnets & Floppy Disks

Code Number:
5G10.11
Demo Title:
Refrigerator Magnets & Floppy Disks
Condition:
Good
Principle:
Magnetic Forces & Fields
Area of Study:
Electricity & Magnetism
Equipment:
Flat pad type refrigerator magnets, fine iron filings.
Procedure:

Place the magnets under a piece of paper and shake on a fine coating of the iron filings.  The iron filings should line up in rows signifying the rows of North/South poles on the flat magnets.  In other words these magnets are made with alternating lines of North and South poles.

References:
  • Stephen Kanim and John R. Thompson, "Magnetic Field Viewing Cards", TPT, Vol. 43, # 6, p. 355, Sept. 2005.
  • Ena S. Bichsel, Brenda Wilson, and Wilhelmus J. Geerts,  "Magnetic Domains of Floppy Disks and Phone Cards Using Toner Fluid",  TPT, Vol. 40, # 3, p. 150, March 2002.
  • Martin F. Schmidt, Jr.,  "Investigating Refrigerator Magnets",  TPT, Vol. 38, # 4, p. 248, April 2000.
  • H. Richard Crane,  "How Things Work - A Thermometer Whose Memory Is a One-Sided Magnet",  TPT, Vol. 37, # 3, p. 148, March 1999.
  • Daniel Lottis, Christopher Baker, and Heather Pounds,  "Giant Magnetoresistance Sensors",  TPT, Vol. 36, # 4, p. 216, April 1998.
  • David G. Haase, "The Mysterious Magnets", TPT, Vol. 34, # 1, p. 60, 1996.
  • "Refrigerator Magnets", Physics From the Junk Drawer, 3rd Edition, The Science House, North Carolina State University, p. 39.

Disclaimer: These demonstrations are provided only for illustrative use by persons affiliated with The University of Iowa and only under the direction of a trained instructor or physicist.  The University of Iowa is not responsible for demonstrations performed by those using their own equipment or who choose to use this reference material for their own purpose.  The demonstrations included here are within the public domain and can be found in materials contained in libraries, bookstores, and through electronic sources.  Performing all or any portion of any of these demonstrations, with or without revisions not depicted here entails inherent risks.  These risks include, without limitation, bodily injury (and possibly death), including risks to health that may be temporary or permanent and that may exacerbate a pre-existing medical condition; and property loss or damage.  Anyone performing any part of these demonstrations, even with revisions, knowingly and voluntarily assumes all risks associated with them.