Abstract:

In recent years in Italian High Schools there has been a strong boost to deal with Special Relativity, a topic which the Italian guidelines for teaching consider fundamental for Modern Physics courses. This argument is a critical issue not only for the students but also for teachers.
Analyzing the results of a questionnaire we submitted last July to Italian teachers, we found out that their primary urgency is to develop laboratorial experiences for Special Relativity.
However, one of the most relevant features of this theory is that it concerns with high velocities and this does not allow to easily perform experiments.

In this talk, we present the results of an experimentation regarding the teaching of Special Relativity we performed in last year classes of High Schools, namely those specializing in scientific studies.
The main innovation of our project consists of a mechanical instrument we use to explain Special Relativity. This tool is a big spacetime diagram in which each event on the grid can be moved along certain hyperbolas-shaped tracks, that represent the surface of constant interval.
Thus, one physically and mechanically performs Lorentz’s transformation 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, times dilation, lengths contraction, relativistic addition of velocities and Doppler’s effect which are the main topics of interest for High Schools.

The idea of using this instrument as a didactic tool was presented successfully for the first time to a group of fifty teachers during an online meeting of the formation course “Fisicamente” organized by our Department (at the end of December 2020) in the context of the National project “Piano Lauree Scientifiche”.

In our 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 second after the lectures.

Keywords:

Special Relativity, spacetime, didactics of Physics, High Schools, laboratory of Special Relativity.