Claudio Fazio

Modelling Mechanical Wave Propagation: Guidelines and experimentation of a teaching–learning sequence

The present paper reports the design process and the experimentation of a teaching–learning sequence about the concept of mechanical wave propagation and the role played by media where waves are propagating. The sequence focuses on the central issue of the relationships between observable phenomena, like macroscopic behaviours of waves, and their interpretation and/or explanation in terms of corpuscular characteristics of media. We describe the design process with respect to the general framework of the Educational Reconstruction Model and the pedagogical tools used. Results of a teaching/learning experiment, involving a sample of 75 high school students, are also reported. Data analysis is mainly based on qualitative research methods. The main focus is on students’ representations of phenomena and on the cognitive strategies put in action in order to modify or support their descriptive and interpretative mental models. Results are discussed by pointing out the efficacy of strategies focusing on the process of constructing predictive conceptual models and by identifying the concept of ‘level of analysis’ as different ways to look at the same phenomenon.

Elucidating the electron transport in semiconductors via Monte Carlo simulations: an inquiry-driven learning path for engineering undergraduates

Within the context of higher education for science or engineering undergraduates, we present an inquiry-driven learning path aimed at developing a more meaningful conceptual understanding of the electron dynamics in semiconductors in the presence of applied electric fields. The electron transport in a nondegenerate n-type indium phosphide bulk semiconductor is modelled using a multivalley Monte Carlo approach. The main characteristics of the electron dynamics are explored under different values of the driving electric field, lattice temperature and impurity density. Simulation results are presented by following a question-driven path of exploration, starting from the validation of the model and moving up to reasoned inquiries about the observed characteristics of electron dynamics. Our inquiry-driven learning path, based on numerical simulations, represents a viable example of how to integrate a traditional lecture-based teaching approach with effective learning strategies, providing science or engineering undergraduates with practical opportunities to enhance their comprehension of the physics governing the electron dynamics in semiconductors. Finally, we present a general discussion about the advantages and disadvantages of using an inquiry-based teaching approach within a learning environment based on semiconductor simulations.

An experiment on the velocity distribution of thermionic electrons

This paper describes an undergraduate experiment that yields the velocity distribution of thermionic electrons by analyzing the I-V characteristics of diodes and triodes. The experiment allows students to focus on the distribution function more than on difficulties arising from the complexity of thermionic emission. By using a simple model, the velocity distribution of thermionic electrons emitted by the vacuum tube cathode can be described by Maxwell’s distribution.

A pedagogical flight simulator for longitudinal airplane flight

This article presents a bi‐dimensional model of flight and describes the implementation of a flight simulator able to describe the different phases of longitudinal flight of a real airplane. After identifying the relevant physical variables, the equations of motion are written and solved using a numerical integration method. Using computer simulations, flight paths and time evolution of the kinematics variables are analyzed for a complete flight of a light commercial airplane. The simulations take into account and reproduce the basic actions of a pilot to control the flight. The main maneuvers involved in pilotage are also predicted and explained in terms of model parameter variations inducing transitions in the phase space. Finally, the steady‐state configurations are analyzed by means of the linearization of equations in order to gain meaningful information about the dynamical stability of the system.

Pedagogical models of surface mechanical wave propagation in various materials

We report on a teaching approach oriented to the understanding of some relevant concepts of wave propagation in solids. It is based on simple experiments involving the propagation of shock mechanical waves in solid slabs of various materials. Methods similar to the generation and propagation of seismic waves are adopted. Educational seismometers, interfaced with computers, are used to detect and visualize the shock waves and to analyse their propagation properties. A qualitative discussion of the results concerning the propagation and the attenuation of the waves allows us to draw basic conclusions about the response of the matter to solicitation impacts and their propagation.

Two Experiments to Approach the Boltzmann Factor: Chemical Reaction and Viscous Flow.

In this paper we discuss a pedagogical approach aimed at pointing out the role played by the Boltzmann factor in describing phenomena usually perceived as regulated by different mechanisms of functioning. Experimental results regarding some aspects of a chemical reaction and of the viscous flow of some liquids are analysed and described in terms of macroscopic variables whose temperature dependence is proportional to the Boltzmann factor. A description of a workshop implementing the approach in the framework of an undergraduate course for engineering education and some preliminary results about its pedagogical relevance are then reported.

The Boltzmann probability as a unifying approach to different phenomena

We discuss a pedagogical approach to the role of the Boltzmann probability in describing the temperature dependence of three simple experimental situations. The approach has been experimented in an introductory course on statistical mechanics for undergraduate engineering students at University of Palermo.

Analysing the Conceptions on Modelling of Engineering Undergraduate Students: A Case Study Using Cluster Analysis

The problem of taking a set of data and separating it into subgroups where the elements of each subgroup are more similar to each other than they are to elements not in the subgroup has been extensively studied through the statistical method of Cluster Analysis . This method can be conveniently used to separate students into groups that can be recognized and characterized by common traits in their answers, without any prior knowledge of what form those groups would take (unsupervised classification). In the last years many studies examined the consistency of students’ answers in a variety of situations. Some of these papers have tried to develop more detailed models of the consistency of students’ reasoning, or to subdivide a sample of students into intellectually similar subgroups by using Cluster Analysis techniques. In this paper we start from a description of the data coding needed in Cluster Analysis, in order to discuss the meanings and the limits of the interpretation of quantitative results. Then a method commonly used in Cluster Analysis is described and the variables and parameters involved are outlined and criticized. Section 3 deals with the application of this method to the analysis of data from an open-ended questionnaire administered to a sample of university students, and discusses the quantitative results. Finally, some considerations about the relevance of this method in Physics Education Research are drawn.

Training Pre-service and In-service Secondary School Teachers: Analysis of Changes in Perceptions About Quantum Physics Concepts and NoS Views

In this work we focus on the study of the changes in perceptions about Quantum Physics concepts and Nature of Science (NoS) Views of secondary school teachers attending three different typologies of professional development courses on Modern Physics . An open-ended questionnaire has been properly developed and administered in order to investigate Quantum Mechanics conceptual issues, NoS views and motivational aspects for all involved teachers. The same questionnaire has been submitted to the teachers both prior-to and after the courses. The analysis of teachers’ pre-instruction answers highlights that the majority of them show several difficulties on both conceptual knowledge and epistemological issues regarding the basic properties of Quantum Physics systems. After instruction, the teachers answered to the questionnaire by showing a clear change of perspective on their view of Quantum Physics concepts. Moreover, our study demonstrates that differences in the educational background of the participating teachers, as well as the typology of professional development course attended, are important when comparing normalized gains. Even in NoS view and motivational aspects, teachers’ answers, collected at the end of the professional development course attended, have shown interesting changes. An overall discussion is finally presented.

Investigating Teacher Pedagogical Content Knowledge of Scientific Inquiry

This paper analyses the scientific inquiry in the context of modelling physical systems and point out some related teaching/learning strategies. Two relevant points are also discussed: (i) the different representations of scientific inquiry held by a sample of secondary school physics teachers and their competencies in conducting investigations aimed at solving scientific problems; (ii) what kind of supports can be supplied to teachers in order to modify their misconceptions about scientific inquiry and develop adequate competences related to Pedagogical Content Knowledge of Scientific Inquiry. The topic will be analysed in the light of some preliminary results of a course for in-service physics teacher education held at University of Palermo in the framework of Establish, an FP7 EU Project.