Underlining some aspects of twin paradox in a high school lesson

In this paper we want to describe one of our lessons held within the educational project “Liceo Matematico” of the Salerno University. We have analyzed the so-called and well-known “Twin Paradox”. It is known that it was initially proposed to discredit the newly published special theory of relativity and after more than 100 years it is now clear that the paradox only leads to an apparent contradiction, which can be fully resolved within the framework of special relativity. Despite the well-established validity of Einsteinian theories, it is still not easy to convey these concepts to students. In fact, due to the young age of the pupils, many textbooks present the principle of relativity and time dilation in a very elementary way. For this reason, it is not uncommon for students to develop misunderstandings, as we believe often happens in the case of the twin paradox.