5K10.60 - Flip Coil

Code Number:
Demo Title:
Flip Coil
Area of Study:
Electricity & Magnetism
Earth Coil (5th Floor), Keithley Electrometer Model 610 B.

Attach the leads from the electrometer to the coil as indicated.  Set the meter to around .01 times 10 to the minus 11 range of the Amps scale.  Flip the coil by pulling the trip knob and observe the meter swing. Reset the coil and fine tune the meter as necessary.  This demo is just meant to show that the earth does have a measurable magnetic field and not for measurement without much more elaborate and cumbersome measuring meters and apparatus.

  • Daniel Lund, Eric Dietz, Xueli Zou, Christopher Ard, Jaydie Lee, Chris Kaneshiro, Robert Blanton, Steven Sun, "Flux Redux:, The Spinning Coil Comes Around Again", TPT, Vol. 55, #1, Jan. 2017, p. 41.
  • R. Akoglu, M. Halilsoy, S. Habib Mazharimousavi, "Simple System to Measure the Earth's Magnetic Field", TPT, Vol. 48, # 8, Nov. 2010, p. 549. 
  • David T. Kagan,  "Measuring the Earth's Magnetic Field in an Introductory Laboratory with a Spinning Coil",  TPT, Vol. 24, # 7, p. 423, October 1986.
  • "Earth Inductor",  Apparatus for Teaching Physics, Reprints of Articles from TPT, April 1963 - Dec. 1971.
  • L. Neel Beard, "Use of a Voltage-to-Frequency Converter to Measure the Integral |E dt", AJP, Vol. 57, #5, May 1989, p. 475.
  • P. Seligmann,  "The Earth's Magnetic Field - A New Technique",  AJP, p. 379, Vol. 55, No. 4, April 1987.
  • Robert D. Smith and Steven B. Eggert, "Recycling the Earth Inductor", AJP, Vol. 52, #3, Mar. 1984, p. 279.
  • Ek - 6:  Freier and Anderson,  A Demonstration Handbook for Physics.
  • David Kutliroff, "94, Wiring a Hula Hoop", 101 Classroom Demonstrations and Experiment For Teaching Physics, p. 207.

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.