Rattleback: Difference between revisions

Revision as of 08:46, 13 April 2006

Revision as of 08:35, 14 April 2006

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

Also known as a "wobblestone", "celtic stone" or simply "celt", the '''rattleback''' is a semi-[[ellipsoid]]al object that reverses its spin direction, when spun one way, but behaves normally if spun the other. Also if held up by one end then let go it begins to spin. The rattleback seems at first sight, to violate [[conservation of angular momentum]].

It is somewhat controversial asdifficult to whatmathematically causesexplain thisthe apparentcauses violation of conservationthe '''rattlebacks''' of angularstrange momentummotion. One theoryexplanation is that its the result of a [http://www.autolev.com/WebSite/SampleProblemRattleback/Rattleback.html non-zero product of inertia]. Basicaqlly it is the broken symmetry in the object that makes it's motion so strange.

Rattlebacks were found by archeologists investigating ancient Celtic and Egyptian sites, and some old Celtic axes demonstrate properties similiar to rattlebacks.