Chaotic Pendulum Hand Spinner

This Chaotic Pendulum Hand Spinner is a compact, hand-held physics toy that demonstrates chaotic motion in an intuitive and playful way. By combining rotational motion with an offset pendulum mass, the spinner produces complex, unpredictable movement patterns that differ with every spin.

The design uses two standard 608 bearings for smooth rotation and a 12.70 mm steel ball (for example from a Geomag set) as the pendulum mass. Small changes in speed or direction lead to noticeably different trajectories, making it an engaging demonstration of nonlinear dynamics and sensitive dependence on initial conditions.

The model is designed for 3D printing and can be printed in common materials such as PLA or PETG. It is suitable as a desk toy, educational aid, or conversation piece for anyone interested in physics, mathematics, or kinetic mechanisms.