Content deleted Content added
David Nelson (talk | contribs) mNo edit summary |
David Nelson (talk | contribs) Added Myths section, design-types information and removed commercial link. |
||
Line 10:
Archeologists who investigated ancient [[Celt|Celtic]] and [[Ancient Egypt|Egyptian]] [[Archaeology|sites]] found celts which exhibited the spin-reversal motion. The [[antiquarian]] word "[[Celt (tool)|celt]]" (the "c" is pronounced as "s") describes [[adze]]-, [[axe]]-, [[chisel]]- and [[hoe]]-shaped [[Lithic analysis|lithic]] tools and weapons.
==Size==
While rattleback [[Artifact|artifact]]s are described as stone with various measurements, most which are sold currently as novelty puzzles and toys are described as plastic with measurements of 3.75-inches length x 0.75-inches width x 0.4375-inches height. Carved wooden rattlebacks are described with a measurement of 6-inches length. One plastic rattleback made and sold by Charles W. Sherburne is described with a measurement of 12-inches length. Glass rattlebacks are described as being tested with unreported measurements. Larger rattlebacks, and those of other materials, aren't yet reported.
Two design types of rattlebacks exist. The first enjoys an asymmetrical base where its rolling axis is skewed. The second enjoys a symmetrical base with off-set weighting at the ends of the rattleback.
==Physics==
Line 21 ⟶ 27:
The amplified mode will differ depending on the spin direction, which explains the rattleback asymmetrical behavior. Depending on whether it is rather a pitching or rolling instability that dominates, the growth rate will be very high or quite low.
This explains why, due to friction, most rattlebacks spin-reversal motion only when spun in the pitching-unstable direction, while they slow down and stop spinning before the rolling instability arises when spun in the other direction.
Other ways to add motion to a rattleback include tapping by pressing down momentarily on either of its ends, and rocking by pressing down repeatedly on either of its ends.
==Myths==
Rattlebacks have been misdescribed and misused as:
*A tool of [[Divination]]
*Influenced by [[Magic (paranormal)|magic]]
*An expression of the object's [[Animism]]
*Influence by the [[Fourth dimension|Fourth Dimension]]
*A demonstration of [[perpetual motion]] "[[free energy]]"
*Influenced by [[Earth's magnetic field]]
*An accurate test of judicial guilt
*Influenced by the [[Coriolis effect]]
==References==
Line 29 ⟶ 57:
[[Hermann Bondi|Bondi KCB FRS, Sir Hermann]]. "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''.
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.
Line 57 ⟶ 85:
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. "ARK: 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.
Line 85 ⟶ 113:
*Keath, Ed. [http://www.123too.com/ ''Turning a celt''.]
*Krasnoukhov, Dr. Vladimir and Anatoli Kalinin. [http://www.jyuta.net/cosmo/vladimir/vladimir.html ''Stubborn Turtles''.]
*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.
| |||