Seeing reality through Einstein's eyes: a teaching proposal for special relativity

The teaching of Special Relativity is still a critical issue not only for students but also for teachers. In this paper, we describe the trial of a learning unit on the Special Relativity topic based on Minkowski's approach through spacetime diagrams, following the results in pedagogical researches in this field. The main innovation of our project consists of a mechanical instrument: it allows to physically and mechanically represent Lorentz’s transformations by hands, exploring the effects of a change of the reference frame. Teachers and students can deal “by eye” with unusual phenomena as the loss of simultaneity, time dilation, length contraction, relativistic addition of velocities and Doppler’s effect which are the main topics of interest for High Schools. During the experimentation, we illustrated to the students the Special Relativity’s phenomenology by using this instrument and evaluated the effectiveness of such an innovative and unusual approach by submitting two questionnaires to the students, one before and the other after the lectures