Dynamics of the bouncing ball
Résumé
We describe an experiment dedicated to the study of the trajectories of a ball bouncing randomly on a vibrating plate. The system was originally used, considering a sinusoidal vibration, to illustrate period doubling and the route to chaos. Our experimental device makes it possible to impose, to the plate, arbitrary trajectories and not only sinusoidal or random, as is generally the case. We show that the entire trajectory of the ball can still be reconstructed from the measurement of the collisions times. First, we make use of the experimental system to introduce the notion of dissipative collisions and to propose three different ways to measure the associated restitution coefficient. Then, we report on correlations in the chaotic regime and discuss theoretically the complex pattern which they exhibit in the case of a sinusoidal vibration. At last, we show that the use of an aperiodic motion makes it possible to get rid of part of the correlations and to discuss theoretically the average energy of the ball in the chaotic regime.