Interactive Double Pendulum Simulation
Hang one pendulum from another and the motion stops being predictable. This simulation lets you start two nearly identical double pendulums together and watch them diverge into completely different paths within seconds.
How to use this simulation
- Set the starting angles and the two arm lengths
- Change the mass of each bob
- Trace the path of the lower bob
What to look for
- Two runs from almost identical starts diverge completely
- The traced path never repeats itself
- Total energy is still conserved despite the unpredictable motion
The physics behind it
A double pendulum is a deterministic system with no random element, yet it is chaotic: tiny differences in the starting conditions grow exponentially. Its equations are fully known, but they are non-linear and coupled, and the resulting sensitivity means long-term prediction is impossible in practice even though the physics is exact.