Wave-particle dualism development from the first speculations on light to modern methods to probe materials: An opportunity for a flipped classroom approach

It is always a big problem to explain students what radiation is and how it can help researchers in understanding the structure of materials in a clear and simple way. The exact comprehension of radiation has followed a very problematic historical excursus. The problem of understanding what light is started to be faced around the VI century B.C.; since that time, a continuous development of ideas and models has characterized the definition of radiation. After Maxwell's equation, the behaviour of light seemed to be well understood, although further enriched, afterwards, by the discoveries in quantum mechanics. Radiation can give rise to several phenomena when interacting with matter. Thus with a correct comprehension of its origin, radiation can constitute a powerful tool in modern science to probe the structure of materials down to the nano-scale and even lower. In this work, scattering phenomena will be considered as effective examples to propose to young students for probing the structure of materials, since these are usually characterized by hierarchical organization of self-assembled structures at different length scales, from atomic to macroscopic distances. In this complex framework, the concept of characteristic distances is pivotal in defining the structure of a material, and can be easily derived from scattering experiments. In this respect, the efforts made in the last century to understand the origin of radiation turned out to be useful in giving researchers the best tool to characterize a given material, at least from its structural point of view. For this reason, modern didactics must take into account for modern approaches to make people aware of these aspects. If bringing kids and young students closer to these arguments is easily achieved by a "learn by doing"approach, this work, structured from the historical point of view and reporting tickling aspects of the debates taken place among peoples over the centuries, represents an opportunity for an interdisciplinary flipped classroom approach.