1Q40.40 - Action-Reaction Demo - Train Demo

See procedure
Code Number:
Demo Title:
Action-Reaction Demo - Train Demo
Action & Reaction
Area of Study:
Electric train on circular track, 12 V DC power supply.

Hook the 12 V power supply to the train track observing the color codes and the directions printed on the track board. The train track and the contact points on the train engine need to be cleaned thoroughly with a soft cloth and the 'Rail-Zip' cleaner before use. The Hobby Corner at Sycamore Mall has this and other accessories for the train. The drive wheel on the engine (the one with the groove in it ) needs to have its traction rings changed periodically. O-rings or rubber bands may be used for this purpose. Do not use more than 15 VDC when running the train.  

The executive magnetic toy will also show this effect.  Spin one of the rotators and watch the other rotate in the opposite direction.

  • J. Guemez, M. Fiolhais. "'Walking' Along a Free Rotating Bicycle Wheel (Round and Round)", TPT, Vol. 53, # 2, Feb. 2015, p. 90.
  • "Figuring Physics", TPT, Vol. 52, # 4, April 2014, p. 247.
  • Paul Dolan, "But Is It Good For Anything?", TPT, Vol. 49, # 6, p. 324, Sept. 2011.
  • Paul Dolan, "What Physics Principle Can I Teach With This?",  TPT, Vol. 49, # 4, p. 249, April 2011. 
  • Stephen J. Van Hook, "Battle of the Merry-Go-Rounds: An Angular Momentum Demonstration", TPT, Vol. 44, # 5, May 2006, p. 304.
  • Akio Saitoh, "Conservation of Momentum - Walking the Boat", TPT, Vol. 23, # 5, May 1985, p. 316.
  • D.P. Wick, M. W. Ramsdell, "Modeling the Motion of a Toy Train Powered with a Time-Dependent Applied Voltage: Educational Implementation and Analysis", AJP, Vol. 72, # 7, July 2004, p. 863.
  • S. Y. Mak and K. Y. Wong, "A Qualitative Demonstration of the Conservation of Angular Momentum in a System of Two Noncoaxial Rotating Disks", AJP, Vol. 57, #10, Oct. 1989, p. 951.
  • Dan Wilson, "Reaction Track",  AJP, Vol. 33, # 10, Oct. 1965, p. 857.
  • Mt- 4,  Freier and Anderson,  A Demonstration Handbook for Physics.
  • M- 772,  "Watch on Watch Glass and Laser",  DICK and RAE Physics Demo Notebook.
  • M-123,  Richard Manliffe Sutton,  Demonstration Experiments in Physics.
  • Robert Ehrlich, "5.2, Walking the Boat", Why Toast Lands Jelly-Side Down, p. 82.
  • Robert Ehrlich, "4.10, A Fan of Angular Momentum Conservation", Why Toast Lands Jelly-Side Down, p. 73.
  • Ed Sobey, Woody Sobey, "Electric Train", The Way Toys Work, 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.