0000000000287912
AUTHOR
R M Sperandeo-mineo
Modelling Mechanical Wave Propagation: Guidelines and experimentation of a teaching–learning sequence
This 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…
An investigation of environmental temperature effects on energy exchange by thermal radiation
The radiative heating or cooling of a body placed in an environment, whose temperature is considered constant is described by Stefan's law. In this paper, an analysis is made of how a time-dependent environmental temperature influences the heating/cooling process. We compare experimental results for a resistor first heated by the Joule effect inside a glass vacuum tube and then cooled under two different conditions: in a bath at a constant temperature and in air. We also discuss a model that describes how the time-dependent tube temperature influences the radiative resistor cooling by identifying the properties of the environment that make the resistor cooling rate linear.
An inquiry-based approach to Maxwell distribution: a case study with engineering students
The concept of distribution is a fundamental component of statistical thinking. This paper describes a teaching approach for it that uses a specific activity related to the field of statistical mechanics. The concept of the velocity distribution of a particle system is dealt with using an inquiry-based approach involving an experimental examination of Maxwell’s distribution. Some outcomes of a teaching experiment held at the Faculty of Engineering of the University of Palermo, Italy are described.
Reply to comment on ‘Measuring longitudinal wave speed in solids: two methods and a half’
We provide a short response to Ganci's comment on our paper 'Measuring longitudinal wave speed in solids: two methods and a half'. The reply faces both the problems involved in the comment: the accuracy of experimental methods and pedagogical aspects.
PEDAGOGICAL CONTENT KNOWLEDGE DEVELOPMENT AND PRE-SERVICE PHYSICS TEACHER EDUCATION: A CASE STUDY
Abstract. This paper addresses the question of how to develop prospective teachers’ pedagogical content knowledge (PCK) in science teacher education. The main focus is on the knowledge transformation process and on the cognitive strategies used to shift prospective teachers’ explanations within the domain of modelling thermal physical phenomena. This study investigates the development of PCK within a group of 28 pre-service physics teachers during the first semester of their two-year post-graduate teacher education program. It focuses on the central issue of the relationships between observable phenomena, like macroscopic thermal properties of matter and their interpretation and /or explanat…
Quantitative and qualitative analysis of the mental models deployed by undergraduate students in explaining thermally activated phenomena
In this contribution we describe a research aimed at pointing out the quality of mental models undergraduate engineering students deploy when asked to create explanations for phenomena/processes and/or use a given model in the same context. Student responses to a specially designed written questionnaire are initially analyzed using researcher-generated categories of reasoning, based on the Physics Education Research literature on student understanding of the relevant physics content. The inferred students’ mental models about the analyzed phenomena are categorized as practical, descriptive, or explanatory, based on an analysis of student responses to the questionnaire. A qualitative analysi…
Measuring longitudinal wave speed in solids: two methods and a half
Three methods to analyse longitudinal wave propagation in metallic rods are discussed. Two of these methods also prove to be useful for measuring the sound propagation speed. The experimental results, as well as some interpretative models built in the context of a workshop on mechanical waves at the Graduate School for Pre-Service Physics Teacher Education, Palermo University, are described. Some considerations about observed modifications in trainee teachers' attitudes to utilizing physics experiments to build pedagogical activities are discussed.
Mechanical models of amplitude and frequency modulation
This paper presents some mechanical models for amplitude and frequency modulation. The equations governing both modulations are deduced alongside some necessary approximations. Computer simulations of the models are carried out by using available educational software. Amplitude modulation is achieved by using a system of two weakly coupled pendulums, whereas the frequency modulation is obtained by using a pendulum of variable length. Under suitable conditions (small oscillations, appropriate initial conditions, etc) both types of modulation result in significantly accurate and visualized simulations.
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 induc…
Construction and validation of a computer-based diagnostic module on average velocity
This article describes the process of building a computer-based diagnostic module concerning the understanding of the average velocity concept. The first step consists of the production of a student model that takes into account student errors and reasoning paths. The computer module formulates its diagnosis by leading users along different patterns foreseen according to the hypothesized student model. Results are reported concerning a correlation analysis between automatic and human diagnoses.
Teaching mechanical oscillations using an integrate curriculum
Abstract A set of teaching materials dealing with harmonic oscillations was developed as part of a research project investigating the influence of different pedagogical tools on physics learning. The materials incorporate simulation software and laboratory activities associated with Teacher and Student Units. The project involved research groups at seven Italian universities and the materials have been trialled in high schools nation‐wide. This paper describes the experimental protocol for the use of these materials in pilot classes and the evaluation of student learning and teacher training results. The intervention was found to improve physics education at school praxis level and to promo…
A Stochastic Approach to Quantum Statistics Distributions: Theoretical Derivation and Monte Carlo Modelling
Abstract. We present a method aimed at a stochastic derivation of the equilibrium distribution of a classical/quantum ideal gas in the framework of the canonical ensemble. The time evolution of these ideal systems is modelled as a series of transitions from one system microstate to another one and thermal equilibrium is reached via a random walk in the single-particle state space. We look at this dynamic process as a Markov chain satisfying the condition of detailed balance and propose a variant of the Monte Carlo Metropolis algorithm able to take into account indistinguishability of identical quantum particles. Simulations performed on different two-dimensional (2D) systems are revealed to…
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.
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.
Electric conduction in semiconductors: a pedagogical model based on the Monte Carlo method
We present a pedagogic approach aimed at modelling electric conduction in semiconductors in order to describe and explain some macroscopic properties, such as the characteristic behaviour of resistance as a function of temperature. A simple model of the band structure is adopted for the generation of electron–hole pairs as well as for the carrier transport in moderate electric fields. The semiconductor behaviour is described by substituting the traditional statistical approach (requiring a deep mathematical background) with microscopic models, based on the Monte Carlo method, in which simple rules applied to microscopic particles and quasi-particles determine the macroscopic properties. We …
A pedagogical approach to the Boltzmann factor through experiments and simulations
The Boltzmann factor is the basis of a huge amount of thermodynamic and statistical physics, both classical and quantum. It governs the behaviour of all systems in nature that are exchanging energy with their environment. To understand why the expression has this specific form involves a deep mathematical analysis, whose flow of logic is hard to see and is not at the level of high school or college students' preparation. We here present some experiments and simulations aimed at directly deriving its mathematical expression and illustrating the fundamental concepts on which it is grounded. Experiments use easily available apparatuses, and simulations are developed in the Net-Logo environment…
Modelling systems of classical/quantum identical particles by focusing on algorithms
A procedure modelling ideal classical and quantum gases is discussed. The proposed approach is mainly based on the idea that modelling and algorithm analysis can provide a deeper understanding of particularly complex physical systems. Appropriate representations and physical models able to mimic possible pseudo-mechanisms of functioning and having predictive validity are developed.
A computer-based diagnostic tutor for average velocity
Abstract The concept of average velocity is often misunderstood, even by students at university level. To analyse student reasoning about average velocity, students who were being instructed in kinematics in an introductory physics course were shown a series of computer animations of two cars moving independently. Their answers to subsequent questions tended to use partial knowledge elements present in the problem. On this basis, a list of eight procedures used by students was drawn up and used as the basis of a computer-based diagnostic tutor, Velo. The performance of Velo is being compared with human tutors.