Ottica geometrica rivisitata
A simple and intuitive model of the functioning of mirrors and lenses is proposed. This model could profitably integrate the traditional way of teaching this topic. The purpose is to make it more effective by giving students a physical interpretation of the way these devices affect light beams. A terminology which distinguishes between the properties of beams and the properties of optical devices is suggested. Mirrors and lenses are treated in a unitary way. The model also provides a simple physical interpretation of the thin lens equation and of the terms that appear in it.