The introduction of the basic physics concepts and the discussion of physics laws are often done in a rather formal way, assuming idealized situations which rigorously follow the theoretical predictions. In general, this approach does not excite an enthusiastic interest in the students, the main reason being that the spontaneous ideas related to many physics concepts are based on everyday life experience and are therefore rather far from the ideal simplification of the theoretical laws. An example is the concept of acceleration, which is approached through kinematics in formal teaching while the students are generally more interested in the dynamical aspects, in particular in those connected with impulsive and transient forces, such as the acceleration of a Ferrari “formula one” car, or the initial sprint in a “100 meters” competition.
In this context, the use of a portable graphic calculator connected with portable sensors can be very useful, because the measurements of real phenomena can be acquired with sufficient accuracy to allow a subsequent analysis, which can relate them to the theoretical laws. Also the possibility of an immediate graphic display helps to develop a first interpretation and understanding of the phenomenon.
In a lab course for the initial preparation of future teachers (SSIS) we have carried on an experimentation of a systematic use of a portable system of this type to help the students to rethink the physics they learned in their university courses, starting from the phenomenon rather than from the law. This is very important in our case, because the majority of our future physics teachers did not graduate in physics but in mathematics and thus tend to privilege the formal mathematical aspects rather than the physics of the phenomenon.
In the presentation, examples will be given of the use of the graphic calculator in the SSIS labs and of the results of the experimentation that followed during the practical training of the students in High School classes.