An after-class chat with classical mechanics professor Fabio Alliguieri got Aluizio Salvador pondering chaotic properties. A theoretical study of the double pendulum, a structure similar to an articulated arm, served as a guide for building his own apparatus, with a light at the tip allowing him to record motion in a time-exposure photograph and demonstrate that minute changes in initial conditions generate huge differences in motion. The next step is to conduct mathematical analyses that prove that oscillations do not follow a repetitive pattern. For students, the experiment underscores the importance of teaching resources that encourage investigation.
Photo submitted by Aluizio Salvador, an undergraduate physics student at the Federal Institute of Paraná, Paranaguá campus.