Subtle dynamics of the chaotic torsion pendulum: a detailed comparison between experiments and numerical simulations

We conduct a detailed experimental and numerical study on the subtle dynamics of the chaotic torsion pendulum (CTP). We first present experimental observations reported by students, and then propose a revised model of CTP based on laws of mechanics and insights about the experiment to understand these observations. Parameters of the revised model are fit using experimental data. The revised model agrees well with experimental observations. The subtle dynamics hidden in these phenomena, from the parameter sensibility to the influences of bisability, are thoroughly exhibited throughout this study, which we hope provides more insight into the nonlinear nature of CTP.