5H40.71 - Ampere's Motor - Railgun

Code Number:
Demo Title:
Ampere's Motor - Railgun
Torque on a Movable Conductor
Area of Study:
Lorentz Force
Ampere's Motor Cart.

Switch on the power supply.  Place the desired rolling conductor on the rails and throw the switch.  The conductor will roll in the direction that you throw the switch.  Let the rolling conductor roll completely off the rails.  DO NOT stop the rolling conductor while it is still on the rails when the rails are powered.  Turn off the power supply when done with the demo.

  • Bruce J. Ackerson, "Special Relativity at Low Relative Velocities", TPT, Vol. 57, #5, May 2019, p. 323.
  • Gabriel I. Font and Anthony N. Dills, "Analyzing Railguns with Excel: Simple Numerical Integration for the Classroom", TPT, Vol. 56, #7, Oct. 2018, p. 436.
  • Marco Fatuzzo, Terrence P. Toepker, "More Track and Field", TPT, Vol. 42, #6, Sept. 2004, p. 351.
  • Frank Weichman, "Force on Current-Carrying Wire", TPT, Vol. 41, # 9, Dec. 2003, p. 547
  • Gay B. Stewart, "Apparatus for Teaching Physics: The Rail Gun", TPT, Vol. 34, # 2, Feb. 1996, p. 122.
  • Stanley O. Starr, Robert C. Young, and Robert B. Cox, 'A Low Voltage "Railgun'", AJP, Vol. 81, #1, Jan. 2013, p. 38.
  • Victor Namias, "Induced Current Effects In Faraday's Law and Introduction to Flux Compression Theories", AJP, Vol. 54, #1, Jan. 1986, p. 57. 
  • Harry F. Meiners, "31-1.3", Physics Demonstration Experiments , p. 909 - 910.
  • Harry F. Meiners, "31-1.4", Physics Demonstration Experiments , p. 909 -910.
  • Richard M. Sutton, "E-135. Rolling Rod in Field of Magnet", Demonstration Experiments in Physics, p. 305 - 306.
  • Borislaw Bilash II, David Maiullo, "Magnetic Slide", A Demo A Day, p. 297.
  • 5H40.71 Demo Pictures, Physics Learning Laboratory, University of Colorado at Boulder.

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.