Rattleback: Difference between revisions

Revision as of 05:15, 9 December 2006

Revision as of 08:45, 9 December 2006

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:''For the fictional animal, see [[Rattleback (rodent)]]''.

[[Image:Celt_with_gemstone_turtles-01.jpg|thumb|300px|RattlebackCarved wooden rattleback]]

A '''rattleback''', also known as a "celt," "Celtic stone" or "wobblestone," is a semi-ellipsoidal [[top]] which will spin on its axis in a preferred direction. But, if spun in the opposite direction, it becomes unstable, "rattles," stops and reverses its spin to the preferred direction.

This spin-reversal motion seems, at first sight, to violate the [[angular momentum|angular-momentum]] conservation law of physics. Moreover, for most rattlebacks, the motion will happen when the rattleback is spun in one direction, but not when spun in the other. These two peculiarities make the rattleback a physical curiosity that has excited human imagination since prehistorical times.

==History==

Archeologists who investigated ancient [[Celt|Celtic]] and [[Ancient Egypt|Egyptian]] [[Archaeology|sites]] found celts which exhibited the spin-reversal motion. The Latin[[antiquarian]] word "[[Celt (tool)|celt]]" (the "c" is pronounced as "s") describes [[adze]]-, [[axe]]-, [[chisel]]- and chisel[[hoe]]-shaped [[Lithic analysis|lithic]] tools and weapons.

==Physics==

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Boardman, Allan J. "The mysterious celt." ''Fine Woodworking'', vol. 53, pp. 68-9. The Taunton Press Inc. Newtown, Conn. July/August 1985.

[[Hermann Bondi|Bondi KCB FRS, Sir Hermann]], [[Order of the Bath|KCB]] [[Royal Society|FRS]]. "The rigid body dynamics of unidirectional spin." ''Proceedings of the Royal Society of London for the Improvement of Natural Knowledge'', vol. A405, pp. 265-74. London. 1986.

Crabtree, Harold. ''An elementary treatment of the spinning tops and gyroscopic motion''. pp. 7, 54, plate I. Longmans, Green & Co. London. 1909.

Crane [[Doctor of Philosophy|Ph.D.]], H. Richard. "How things work: The rattleback revisited." ''The Physics Teacher'', vol. 29(5), pp. 278-9. American Association of Physics Teachers. College Park, Md. 1991.

Edge [[Doctor of Philosophy|Ph.D.]], Ronald D. and Richard Lee Childers [[Doctor of Philosophy|Ph.D.]]. "String and sticky tape: Curious celts and riotous rattlebacks." ''The Physics Teacher'', vol. 37(2), p. 80. American Association of Physics Teachers. College Park, Md. 1999.

Elliott, W.A. ''The inside story of the whirlygig!'' W.A. Elliott Co., Toronto.

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Magnus, Karl. ''The stability of rotations of a non-symmetrical body on a horizontal surface''. Festschrift Szabo, pp. 19-23, Berlin. 1971.

McGeer [[Doctor of Philosophy|Ph.D.]], Tad and Leigh Hunt Palmer [[Doctor of Philosophy|Ph.D.]] "Wobbling, toppling and forces of contact." ''American Journal of Physics'', vol. 57, pp. 1089-98. American Association of Physics Teachers. College Park, Md. 1989.

Moffatt [[Doctor of Philosophy|Ph.D.]] [[Royal Society|FRS]], Henry Keith. "Talk for the 50th anniversary." ''Journal of Fluid Mechanics'', Cambridge University Press. Cambridge, England. 2006.

Satterly [[Doctor of Science|D.Sc.]] [[Royal Society of Canada|FRSC]], John. "Induced rocking." ''American Journal of Physics'', vol. 26, pp. 625-7. American Association of Physics Teachers. College Park, Md. 1958.

Satterly [[Doctor of Science|D.Sc.]] [[Royal Society of Canada|FRSC]], John. "Rocking experiment with two degrees of freedom." ''American Journal of Physics'', vol. 21, 267-73. American Association of Physics Teachers. College Park, Md. 1953.

Satterly [[Doctor of Science|D.Sc.]] [[Royal Society of Canada|FRSC]], John. "Three interesting instances of rocking." ''American Journal of Physics'', vol. 23, pp. 14-26. American Association of Physics Teachers. College Park, Md. 1955.

Satterly [[Doctor of Science|D.Sc.]] [[Royal Society of Canada|FRSC]], John. "Vibrational dynamics with lenses, mirrors and prisms." ''American Journal of Physics'', vol. 23, pp. 562-81. American Association of Physics Teachers. College Park, Md. 1955.

Sherburne, Charles W. "Scientific demonstration toy." U.S. Design 210,947. Filed: Nov. 12 1995. Patented: May 7, 1968. San Pedro, Calif.

Walgate [[Doctor of Philosophy|Ph.D.]], Robert. "Tops that like to spin one way." ''Nature'', vol. 323, p. 204. Nature Publishing Group, London. 1986.

[[Jearl Walker|Walker Ph.D., Jearl]]. "The mysterious 'rattleback': A stone that spins in one direction and then reverses." ''Scientific American'', pp. 172-84. Scientific American Inc. New York. 1979.

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[[Gilbert Walker|Walker FRS, Sir Gilbert Thomas]]. "On a dynamical top." ''Quarterly Journal of Pure and Applied Mathematics'', vol. 28, pp. 175-84. International Press. Somerville, Mass. 1896.

Wheeler [[Doctor of Philosophy|Ph.D.]], Nicholas A. ''Rattlebacks -- How do they work?'' Reed College Department of Physics. Portland, Ore.

==External links==

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*4Physics.com: [http://www.4physics.com/phy_demo/rattleback.htm ''The amazing rattleback!'']

*Bondi KCB FRS, Sir Hermann. KCB FRS. [http://links.jstor.org/sici?sici=0080-4630(19860609)405%3A1829%3C265%3ATRBDOU%3E2.0.CO%3B2-M "The rigid body dynamics of unidirectional spin."] ''Proceedings of the Royal Society of London for the Improvement of Natural Knowledge'', vol. A405, pp. 265-74. 1986.

*Brown University: [http://physics.brown.edu/physics/demopages/Demo/solids/demos/torque.html ''Torque of the devil''.] physics demonstration.

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*Pippard, A.B. [http://www.iop.org/EJ/abstract/0143-0807/11/1/112 "How to make a celt or rattleback."] ''European Journal of Physics'', vol. 11, pp. 63-4. Institute of Physics. 1990.

*Simon Fraser University: [http://www.sfu.ca/~closari/projects/ensc100/index.htm ''Rattleback''.] Engineering Science 100 Tutorial Group Nu. Burnaby, British Columbia, Canada.

*Simon Fraser University: [http://www.sfu.ca/physics/ugrad/courses/teaching_resources/demoindex/mechanics/mech1q/celt.html ''Celt''.] physics demonstration. Burnaby, British Columbia, Canada.

*Singmaster, David. [http://www.g4g4.com/MyCD5/SOURCES/SOURCE4.DOC ''Celts -- Rattlebacks''.] South Bank University. London. 2004.