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

We conduct a detailed experimental and numerical study on the subtle dynamics of 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 parameter sensibility to influences of bistability and noise, are thoroughly exhibited through this study, hoping to provide more insights to the nonlinear nature of CTP.