Chaos Lab

Continuous flow · dim 4

Double pendulum

The simplest mechanical system that exhibits chaotic motion. Conservative (no friction) chaos for moderate-to-large initial energies.

Bob traces of two double pendulums starting ε ≈ 10⁻³ apart: SDIC visualised.

Equations

Coupled Euler-Lagrange equations for two pendula joined end to end (4-D phase space: θ_1, θ_2, dθ_1/dt, dθ_2/dt).

At a glance

Parametersm_1, m_2, l_1, l_2, g, initial conditions
Chaotic formoderate-to-large initial angles
HistoryStudied since Daniel Bernoulli (1733); chaos understood in the 1960s-70s.

Try it

Open the interactive playground at /tools/double-pendulum.

See also

Test your knowledge

8-question flashcard quiz on double pendulum

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