**4. Working hypothesis**

The training to promote the teaching-learning in Earth Sciences should pass by more effective educational approach. The use of educational tools and of learning objects seems to be particularly effective and involving.

It is a widespread belief, based on tested and shared practices, that Science teaching-learning should be based primarily on active teaching methodological approaches. In the case of the so-called hard disciplines, Physics and Chemistry, the experimental and laboratory approach is a widespread and shared heritage: the use of machines, tools, and objects allows to develop experimental activities with the increasing complexity. The approach is generally based on the scientific method of Galilean memory, scientifically correct but with little space left for intuition and autonomous reasoning.

In other scientific disciplines, as biology and geology, experimental practices are perhaps less widespread. But when they are used, they allow the development of operative paths favoring investigation and promoting curiosity: but especially they push the student toward the research, at first guided by the teachers/experts, then gradually let to become autonomous.

In Earth Sciences, the hands-on approach is naturally part of the teaching of petrography and paleontology, where the learning object can be manipulated, observed, studied, analyzed, and compared. On the contrary, complex phenomena, as global tectonics, earthquakes, or faults and folds, require a different approach.

It is not easy, for an "uninitiated," to appreciate the history of a rock, the dynamics of a landslide, the richness of information and connections of a stratigraphic sequence, and the beauty of a fold. Then, the teacher's task must not stop to illustrate scientifically the phenomenon of the fold, the rock in which it was formed: he must also to discover the link with Physics (temperature and pressure), Chemistry (composition of materials), and geological history (the event that formed it); he should also help to discover the fold's beauty, as if it were a masterpiece of nature.

It is not easy to discover alone, the not always understandable beauties of geology.
