7F10.31 - Time Dilation - Twin Paradox

Code Number:
Demo Title:
Time Dilation - Twin Paradox
Time Contraction
Area of Study:
Modern Physics
HS tape - Mechanical Universe II #17.

A twin paradox example is available on the Mechanical Universe tape.

  • Ron A. Pepino, Risley W. Mabile, "A Misconception Regarding the Einstein Equivalence Principle and a Possible Cure Using the Twin Paradox", TPT, Vol. 61, #2, Feb. 2023, p. 118.
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  • Walter Bruce Richards, "Understanding a Paradox in Special Relativity", TPT, Vol. 59, #4, April 2021, p. 284.
  • Brian Patterson, Mario Serna, M. Alina Gearba, Robert Olesen, Patrick O'Shea, Jonathan Schiller, David Emanuel, Jerry F. Sell, M. Shane Burns, Michael D. Leveille, Armand R. Dominguez, Brian B. Gebhard, Samuel E. Huestis, Jeffery Steele, "An Undergraduate Demonstration of Gravitational Time Dilation", TPT, Vol. 58, #4, April 2020, p. 268.
  • Bret Underwood and Yunxiao Zhai, "Moving Phones Tick Slower: Creating an android App to Demonstrate Time Dilation", TPT, Vol. 54, #5, May 2016, p. 277.
  • Thomas W. Murphy Jr., "Confronting Twin Paradox Acceleration", TPT, Vol. 54, #5, May 2016, p. 272. 
  • Fred Behroozi, "A Simple Derivation of Time Dilation and Length Contraction in Special Relativity", TPT, Vol. 52, #7, Oct. 2014, p. 410.
  • Ira Mark Egdall, "Teaching Special Relativity to Lay Students", TPT, Vol. 52, #7, Oct 2014, p. 406.
  • Frank Wang, "Moving Clocks Do Not Always Appear to Slow Down: Don't Neglect the Doppler Effect", TPT, Vol. 51, #3, Mar. 2013, p. 154.
  • J. Ronald Galli, Farhang Amiri, "The Square Light Clock and Special Relativity", TPT, Vol. 50, #4, Apr. 2012, p. 212.
  • Elisha Huggins, "Special Relativity in Week One: 4) Lack of Simultaneity", TPT, Vol. 49, #6, Sept. 2011, p. 340.
  • Elisha Huggins, "Special Relativity in Week One: 3) Introducing the Lorentz Contraction", TPT, Vol. 49, #5, May 2011, p. 302.
  • Elisha Huggins, "Special Relativity in Week One: 2) All Clocks Run Slow", TPT, Vol. 49, #4, Apr. 2011, p. 220.
  • Elisha Huggins, "Special Relativity in Week One: 1) The Principle of Relativity", TPT, Vol. 49, #3, Mar. 2011, p. 148.
  • Bernhard Rothenstein and Stefan Popescu, "Relativistic Velocity Addition Law from Machine Gun Analogy", TPT, Vol. 47, #1, Jan. 2009, p. 43.
  • Lisa N. Daly and George K. Horton, "The Universality of Time Dilation and Space Contraction", TPT, Vol. 32, #5, May 1994, p. 306.
  • Barry R. Holstein, "Gravitational Twins Revisited", TPT, Vol. 23, #6, Sept. 1985, p. 364.
  • Michael Bradley and Jack Higbie, "Gravitation Twins", TPT, Vol. 22, #1, Jan. 1984, p. 34.
  • A. C. Melissinos, "A Triplet Paradox", TPT, Vol. 20, #1, Jan. 1982, p. 53.
  • John Walters, "Time Dilation and The Lorentz Contraction", TPT, Vol. 20, #1, Jan. 1982, p. 42.
  • Donald E. Hall, "Intuition, Time Dilation, and the Twin Paradox", TPT, Vol. 16, #4, Apr. 1978, p. 209.
  • Barry Leonard Werner, "The Twin Paradox Revisited", TPT, Vol. 13, #7, Oct. 1975, p. 422.
  • Paul G. Hewitt, "The Author Replies", TPT, Vol. 12, #9, Oct. 1974, p. 389.
  • G. McGuire, Henry M. Bradford, and Peter A. Fowell, "Twins and Time", TPT, Vol. 12, #7, Oct. 1974, p. 388.
  • Paul G. Hewitt, "On Teaching About Twins and Time", TPT, Vol. 11, #9, Dec. 1973, p. 519.
  • Thomas Müller, Andreas King, and Daria Adis, "A Trip to the End of the Universe and the Twin 'Paradox'", AJP, Vol. 76, #4, Apr. 2008, p. 360.
  • Daniel F. Styer, "How Do Two Moving Clocks Fall Out of Sync?  A Tale of Trucks, Threads, and Twins", AJP, Vol. 75, #9, Sept. 2007, p. 805.
  • Antony Eagle, "A Note on Dolby and Gull on Radar Time and the Twin 'Paradox'", AJP, Vol. 73, #10, Oct. 2005, p. 976.
  • E. Minguzzi, "Differential Aging From Acceleration: An Explicit Formula", AJP, Vol. 73, #9, Sept. 2005, p. 876.
  • Carl E. Dolby and Stephen F. Gull, "On Radar Time and the Twin 'Paradox'", AJP, Vol. 69, #12, Dec. 2001, p. 1257.
  • Maria B. Cranor, Elizabeth M. Heider, and Richard H. Price, "A Circular Twin Paradox", AJP, Vol. 68, #11, Nov. 2000, p. 1016.
  • Edward A. Desloge and R. J. Philpott, "Comment on 'The Case of the Identically Accelerated Twins' by S. P. Boughn [Am. J. Phys. 57, 791-793 (1989)]", AJP, Vol. 59, #3, Mar. 1991, p. 280.
  • Tevian Dray, "The Twin Paradox Revisited", AJP, Vol. 58, #9, Sep. 1990, p. 822.
  • Richard A. Muller, "The Twin Paradox in Special Relativity", AJP, Vol. 40, #7, July 1972, p. 966.
  • Daniel M, Greenberg, "The Reality of Twin Paradox Effect", AJP, Vol. 40, #5, May 1972, p. 750.
  • Barry R. Holstein and Arthur R. Swift, "The Relativity Twins in Free Fall", AJP, Vol. 40, #5, May 1972, p. 746.
  • Leo Levi, "The "Twin Paradox" Revisited", AJP, Vol. 35, #10, Oct. 1967, p. 968.
  • Barbara Goss Levi, "Relativistic Effects Seen at Everyday Distances and Speeds", Physics Today, Vol. 63, #11, Nov. 2010, p. 16.
  • Rick Beyer, "Ticket to Ride", The Greatest Science Stories Never Told, p. 100.
  • John G. Cramer, "The Alternative View - The Twin Paradox Revisited", Analog Science Fiction/Science Fact, p. 101.
  • "Puzzles and Paradoxes", Selected Reprints Published for The American Association of Physics Teachers by the American Institute of Physics.
  • Stan Gibilisco, "The Twin Paradox", Puzzles, Paradoxes and Brain Teasers, p. 71 - 72.
  • Stan Gibilisco, "Time Travel", Puzzles, Paradoxes and Brain Teasers, p. 69 - 71.
  • Stan Gibilisco, "Time Travel", More Puzzles, Paradoxes and Brain Teasers, p. 21.

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.