STUDY OF STUDENTS’ CONCEPTIONS OF PREDICTABILITY IN PHYSICS - EXPERIMENTAL PROGRAM FOR TEACHING BASIC NATURE OF CHAOS

In a deterministic system, solving equations of motion with certain initial conditions gives a unique trajectory according to causality. In a periodic system, like a harmonic oscillator, the trajectory does not depend so much on the initial conditions, as a small change in the initial conditions only leads to a small change in the trajectory. However, in a chaotic system, a small change in the initial conditions significantly modifies the time evolution thereafter. The current paper reveals that few physics-major undergraduate students understand the importance of the initial conditions when solving equations of motion. In particular, no one could perceive the existence of a chaotic motion. Accordingly, an experimental program is proposed that demonstrates the basic nature of chaos using a double pendulum, a well-known chaotic oscillator. Observation of the motion intuitively teaches that its sensitive dependence on the initial conditions makes it difficult to predict a chaotic time evolution over a long period of time.