THE PHYSICS LABORATORY FOR THE SECONDARY SCHOOL: FROM CLASSICAL TO MODERN METHODS

During the physics laboratory classes the pupils have to discover the most prominent scientists and their experiments, they have to realize themselves the experiments and connect the past with the present and the future using more or less sophisticated instruments.
The goal of the present work is to show that the pupils can get acquainted with the important achievements of the physics through experiments that range from simple ones imagined by themselves to more complicated ones where the use of the graphing calculators is of decisive importance.
The contribution reports on the results obtained with a sixth grade class from a secondary school from Padova in studying the measurement of the temperature.
The laboratory started with an incursion in the past to discover the scientists who first invented the thermometer, the various types of thermometers and temperature scales. After being acquainted with the basic working principles of the temperature measuring devices the pupils have to build themselves a thermometer by using materials of common use. The pupils are then trained to evaluate the temperature of different objects with their senses by comparing the feeling produced by touching various objects with the temperature values measured with a thermometer. The pupils are also shown how to use a medical thermometer for measuring the body temperature and how to measure the boiling temperature of the water and to trace graphically the dependence of the water temperature on the time.
After this we introduced the use of the RTL (Real Time Laboratory) system for measuring the temperature of different objects, of the body and of the boiling water. The RTL system comprises all the instruments for acquiring and analyzing the experimental data in real time and it consisted of the temperature sensors, readout interface and graphing calculator.
Through the classical method when measuring the body temperature one can have only the final reading of the temperature and no information on its evolution in time, especially important if the pupils are moving or running during the measurement. By using the temperature sensors one can directly visualize on the calculator the variation of the body’s temperature at any moment and the pupil can understand what happens when they move or sweat. The use of the RTL system makes the tracing of the graphs easier and faster. In fact, once all the parameters are set the calculator acquires continuously the data and produces the graph in real time. This way, the pupils can see immediately the effects of any change in the status of the subject under investigation. The use of the RTL system allowed for a faster a more accurate performance of the measurements and permitted the repetition of measurements several time under different conditions.