Double Pendulum — Chaotic Motion Demonstration

Two pendulums linked at a joint. Perfectly deterministic equations of motion. Completely unpredictable behaviour. This is chaos theory made physical.

The double pendulum is the canonical example of deterministic chaos. Its equations are derived from Newtonian mechanics with no approximations — and yet it is exquisitely sensitive to initial conditions. Start it from nearly the same position twice and the trajectories diverge exponentially. The tiniest quantum fluctuation matters. It is why long-term weather forecasting is impossible in principle, not just in practice.

What you can demonstrate:

• Sensitive dependence on initial conditions
• Lyapunov exponents and the butterfly effect
• The difference between determinism and predictability
• Lagrangian mechanics and generalized coordinates
• Phase space and strange attractors

Specifications: Polished stainless steel arms · Low-friction precision bearings · Magnetic base · Optional LED trace attachment sold separately · Height: 40cm

Hypnotic to watch. Impossible to predict. Entirely explained by F = ma.