= Double pendulum demonstration
The University of Toronto's institutional demonstration “Chaotic Behaviour (Double Pendulum)”, activity Me-020, uses a metal stand with four leveling feet and a pendulum arm carrying a white dot. Preparation includes leveling the stand and correcting any wobble. The instructions call for holding the arm vertically upward and releasing it; the readout is the visible motion of the dot. A further comparison inserts a metal dowel in a groove on the release arm and repeats the release at the same location. Keeping the stand steady and repeating the release position provide practical controls. The page supplies no numerical <angle> trace or calibrated timing, and does not explain the dowel's mechanical effect. It therefore documents a qualitative release demonstration, without quantitatively testing the equal-<point mass> model. Its extended arms also have <moments of inertia> absent from massless rods. Irregular visible motion alone does not establish <sensitive dependence on initial conditions>.<Chaotic Behaviour (Double Pendulum) (University of Toronto Department of Physics)>[Chaotic Behaviour (Double Pendulum), activity Me-020, Description: leveling, vertical release, white-dot readout, dowel insertion and repeated release; Apparatus]{ref}
A separate comparison with <normal modes of a double pendulum> would require small downward releases and measurement of both <angles> over <time>. The actual arm <masses>, <centres of mass> and <moments of inertia> would first have to enter the <Lagrangian>. The upward release in this demonstration explores a different regime from <small oscillations> about the downward <stable equilibrium>.
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