Galileo recognises pendulum swing According to Vincenzo Viviani (1622–1703), who was Galileo Galilei's last student and author of his master's biography, Galileo first recognised the isochronous properties of a pendulum while observing the swinging of a lit chandelier in Pisa Cathedral when he was student and not yet a famous scientist, sometime between 1581 and 1610. Viviani’s famous story has long been dismissed as a myth, as the chandelier in question was installed in the Cathedral after Galileo’s student days. However, Galileo’s interest in pendulums is documented in his own papers some twenty years later, and he conducted several experiments with pendulums during his career. In 1635 and 1636, he even claimed to be able to build a clock that would be accurate within one minute by relying on the isochronicity of the pendulum, and that it would not be hard to design an escapement for this pendulum. Regrettably, he never did build this clock, but his notes and drawings survived. These were used and developed by Christiaan Huygens, who designed the first domestic pendulum clock in 1656. Reference Wootton, D. 2010. Galileo: Watcher of the skies. New Haven and London: Yale University Press, pp. 18–21, 71. Image Credit AIS5354703 Galileo Galilei watching the chandelier swinging back and forth at the Pisa Cathedral 1582, 1841 by Sabatelli, Luigi (1772-1850); Museo di Storia Naturale dell'Universita' degli Studi di Firenze, Florence, Tuscany, Italy; (add.info.: Galileo Galilei (1564-1642); © Iberfoto / Bridgeman Images https://www.bridgemanimages.com/en-US/sabatelli/galileo-galilei-watching-the-chandelier-swinging-back-and-forth-at-the-pisa-cathedral-1582-1841/painting/asset/5354703
