Una versione moderna dell’esperimento di Fourier sulla conduzione termica entro un anello di metallo

This work deals with a famous historical experiment, i.e. the experiment that allowed Fourier to establish his theorem about the series expansion of a periodic function. In our experiment, that deals also with many aspects of the theory of heat, we warmed up an aluminium ring by means of a flame pointed towards a single point of the ring. Then, after having suppressed the flame, we monitored the temperature of the ring by means of 16 thermocouples connected on-line with a computer. While the ring was cooling down, the temperature profile was found to evolve towards an almost perfect sinusoidal profile, just as Fourier guessed, relying on two facts: (a) the temperature profile along a ring can always be expanded in a series of sines and cosines; (b) the different harmonics of this series disappear more rapidly if their order is high.