Earth Coil (5th Floor), Keithley Electrometer Model 610 B
Earth Coil (5th Floor), Keithley Electrometer Model 610 B

 

Code Number: 5K10.60

Demo Title: Flip Coil

Condition: Excellent

Principle: Induction

Area of Study: Electricity & Magnetism

Equipment: 

Earth Coil (5th Floor), Keithley Electrometer Model 610 B.

Procedure:

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.

References:

  • 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.
  • Thomas B. Greenslade, Jr., "Daniel Davis, Jr., and His Manual of Magnetism", AJP, Vol. 93, #6, June 2025, p. 477.
  • 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.
  • William C. Smith, Fred W. Inman, Carl E. Miller, "Improved Apparatus for Measuring the Earth's Magnetic Field", AJP, Vol. 44, #9, Sept. 1976, p. 893.
  • 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.