In this presentation a number of animations and simulations are utilized to understand and teach ... more In this presentation a number of animations and simulations are utilized to understand and teach some of the pendulum's interpretations related to what we now see as the history of energy conservation ideas. That is, the accent is not on the pendulum as a time meter but as a constrained fall device, a view that Kuhn refers back to Aristotle. The actors of this story are Galileo, Huygens, Daniel Bernoulli, Mach and Feynman (Leibniz's contributions, however important, are not discussed here). The "phenomenon" dealt with is the swinging body. Galileo, focussing on the heights of descent and ascent rather than on trajectories, interprets the swinging body in both ways (time meter and constrained fall), establishes an analogy between pendulums and inclined planes and eventually gets to the free fall law. Huygens expands the analysis to the compound (physical) pendulum and as a by-product of the search for the centre of oscillation (time meter) formulates a version of the vis viva conservation law (constrained fall). Both Galileo and Huygens assume the impossibility of perpetual motion and Mach's history will later outline and clarify the issues. Daniel Bernoulli generalises Huygens results and formulates for the first time the concept of potential and the related independence of the work done from the trajectories (paths) followed: vis viva conservation at specific positions is now linked with the potential. Feynman's modern way of teaching the subject shows striking similarities. Multimedia devices enormously increase the possibility of understanding what is a rather physically complex and historically intriguing problem. Teachers and students are in this way introduced to the beauties of epoch-making scientific research and to its epistemological implications.
Uploads
Papers by Lidia Falomo