Painting patterns of light with two connected pendulums

What is it about?

The pendulum is a fundamental system in physics, its so-called harmonic oscillations find relevance in many different fields. 

The motion of a single pendulum can be described quite easily. However, if you look at the double pendulum, you quickly see a seemingly random, unpredictable dynamic. In our installation, an ultraviolet laser mounted on the tip of the pendulum creates an afterglow on a phosphorescent film that illuminates the path of the pendulum. The line describing the motion of the pendulum is called its trajectory.

Details and Theory

The theoretical description of this trajectory leads to coupled nonlinear equations. Nonlinear systems generally have the property that a small change in the initial conditions causes a large change in the dynamics.

If you drop the pendulum several times from almost the same position, you get a completely different pattern each time. If all initial parameters were exactly adjustable (which is impossible in reality), the chaos of the double pendulum could be controlled – hence it is called deterministic chaos.