Un modello esponenziale per l’attenuazione della luce

It is empirical evidence that some substances absorb light radiation by transmitting only a fraction of it. The reduction in the intensity of light transmitted through a medium seems to depend on the thickness of the substance. However, in what way? To answer this question, an educational experience can be designed that allows students in grades 11-14 to study the phenomenon of light attenuation in an experimental setting, with the help of a smartphone and the Phyphox app. The activity we propose in this contribution encourages students to construct a mathematical model that relates the amount of light transmitted by a material to the thickness of the medium. The choice of an exponential model to describe the phenomenon leads to the discovery of the Lambert-Beer law. The use of the smartphone as a measurement tool is functional to experiment with an innovative model of interdisciplinary laboratory teaching, which extends from physics to mathematics and science in a perspective of mutual interaction and integration between disciplines.