Due 'paradossi meccanici' della Collezione Storica degli Strumenti di Fisica dell'Università di Palermo

Many instruments of the Historical Collection of the Physics Instruments of the University of Palermo date back to the early nineteenth century, when experimental Physics begun to be taught in university studies by using instruments and apparatuses in the classroom to illustrate the laws of Physics. Among the various instruments belonging to the Collection, there are also the so-called 'paradoxes', instruments with surprising properties that do not seem to follow the laws of Physics. In this article we analyze two 'mechanical paradoxes' of the Collection and discuss their possible educational use.