Rethinking the memorial in a Black Belt landscape: Planning, memory and identity of African-Americans in Alabama

Although many old sites are well preserved, many sites of historical and cultural value in the United States are disappearing due to their abandonment. In some cases, the condition of these sites makes restorers’ work very difficult. In other cases, in order to recover blighted local economies, administrations and cultural institutions are adopting strategic spatial plans to attract tourists or accommodate historical theme parks. However, recent scholarly interest in the interaction of history and collective memory has highlighted these sites. Even if the memory of some historical sites is fading quickly, this memory is receiving greater attention than in the past in order to enhance local identity and strengthen the sense of community. This article examines a number of plans and strategies adopted to give shape to the memorial landscape in Alabama, thereby documenting and exploring some key relations between city planning and the commemoration of African-American history

An educational path for the magnetic vector potential and its physical implications

We present an educational path on the magnetic vector potential A addressed to undergraduate students and to pre-service physics teachers. Starting from the generalized Ampere-Laplace law, in the framework of a slowly varying time-dependent field approximation, the magnetic vector potential is written in terms of its empirical referent, i. e. the conduction current. Therefore, once the currents are known, our approach allows a clear and univocal physical determination of A overcoming the mathematical indeterminacy due to the gauge transformations. We have no need to fix a gauge, since for slowly varying time-dependent electric and magnetic fields, the natural gauge for A is the Coulomb one. We stress the difference between our approach and those usually presented in the literature. Finally, a physical interpretation of the magnetic vector potential is discussed and some examples of calculation of A are analysed

Nov pogled na spomenike v pokrajini Črnega pasu: načrtovanje, spomin in identiteta Afroameričanov v Alabami

Čeprav so mnogi stari kraji v ZDA dobro ohranjeni, veliko območij zgodovinske in kulturne vrednosti zaradi opuščanja izginja. V nekaterih primerih imajo restavratorji zaradi stanja teh krajev težko delo, v drugih primerih pa uprave in kulturne ustanove za izboljšanje lokalnega gospodarstva uvajajo strateške prostorske načrte, s katerimi želijo pritegniti turiste in urediti zgodovinske tematske parke. Novejše raziskave odnosa med zgodovino in kolektivnim spominom pa so ta območja postavile pod drobnogled. Čeprav spomin za nekatera zgodovinska območja hitro izgineva, dobiva več pozornosti kot v preteklosti, s čimer se krepita lokalna identiteta in občutek pripadnosti skupnosti. V članku je obravnavano več načrtov in načrtovalskih strategij, ki so bili razviti za oblikovanje spomeniške pokrajine v Alabami, dokumentirani in preučeni pa so tudi nekateri ključni odnosi med načrtovanjem mest in obeleževanjem zgodovine Afroameričanov

“I (critically) think, therefore I am”: Thomson’s atomic model and the ineffectiveness of physics education

INTRODUCTION In 1904, Thomson proposed an accurate atomic model (Thomson, 1904), with a precise geometrical structure, intended as a heuristic device and aimed to explain the stability and unity of atomic phenomena, both from a chemical and electrical point of view. Therefore, the plum pudding image - commonly used in textbooks (Walker, 2017; Amaldi, 2020; Halliday, 2021; Cutnell, 2022) and familiar to teachers and students, but never used by Thomson - is due to a deep conceptual misunderstanding or perhaps to a teasing of the model. A WIDESPREAD LACK OF CRITICAL THINKING In physics courses, Thomson’s model is presented after electrostatic issues and described as a spherical distribution of positive charge with electrons randomly arranged in it (as the plums in an alleged “plum pudding”); nevertheless, the awareness that such a configuration cannot be in stable conditions unexpectedly does not arise, showing a widespread failure in using electrostatic knowledge previously acquired in a different context. Moreover, it is known that accelerated charges emit and therefore a stable planetary model cannot be possible. Thomson's model - which supposes electrons in motion, to obtain stable configurations - clearly shows the inaccuracy of this absolute statement: the problem is not the emission, but rather its amount (since collisions can provide a way to regain small energy losses). It is therefore necessary to become aware that, without calculations, the merely qualitative aspects can be misleading. Students and teachers do not usually question themselves how a model proposed by a great physicist - as Thomson was, having won the Nobel Prize in 1906 - could only be an inconsistent qualitative pattern, rather than a rigorous mathematical structure, capable of both explaining phenomena and making predictions. This lack of critical thinking compromises the foundations of physics education, and asks for careful considerations about the real effectiveness of actual physics courses in schools and universities. In this work that we are presenting, we will deal with this theme, which is not an isolated case, since also in other situations (like while dealing with the photoelectric effect and the Compton effect) coherency problems at an elementary level appear, showing the inefficacy of physics education in creating the mental conceptual structures required to critically analyse what is usually taught and learned. REFERENCES Amaldi, U. (2020). Il nuovo Amaldi per i licei scientifici blu (Vol.3). Bologna: Zanichelli. Cutnell, J. D., Johnson, K. W., & Young, D. (2022). Physics: International Adaptation (12th ed.). Hoboken, NJ: Wiley. Halliday, D., & Resnick, R. (2021). Fundamentals of Physics (12th ed.). Hoboken, NJ: Wiley. Thomson, J. J. (1904) On the Structure of the Atom. Philosophical Magazine, 7(39), 237-265. Walker, J. S. (2017). Physics (5th ed.). Bellingham, WA: Western Washington University

Motion of a superconducting loop in an inhomogeneous magnetic field: a didactic experiment

We present an experiment conductive to an understanding of both Faraday's law and the properties of the superconducting state. It consists in the analysis of the motion of a superconducting loop moving under the influence of gravity in an inhomogeneous horizontal magnetic field. Gravity, conservation of magnetic flux, and friction combine to give damped harmonic oscillations. The measured frequency of oscillation and the damping constant as a function of the magnetic field strength (the only free parameter) are in good agreement with the theoretical model.Comment: 9 pages, 5 figure

L’aspetto fondamentale della teoria nella didattica della fisica quantistica

Most educational presentations of quantum physics show interpretative difficulties dating back to the early ‘900 and lacking a suitable analysis of the meaning of “reality” that emerges from the theory. No wonder, therefore, that school paths derived from them often leave students confused, at all age levels. The main problem stems from the lack of awareness of the nature of physical theories and their relationship with the outcome of possible experiments. We will discuss this nature both, from the epistemological and the educational point of view and give indications to provide an increasingly solid foundation for the educational reconstructions of the content, for quantum as well as for classical physics, and therefore, to contribute to create conditions for a better teaching of physics in general.La maggior parte delle presentazioni didattiche della fisica quantistica mostra difficoltà interpretative che risalgono ai primi anni del ‘900 ed è carente sull’analisi del significato di “realtà” che emerge dalla teoria. Non stupisce, perciò, che i percorsi scolastici che ne derivano lascino spesso confusi gli studenti, a tutti i livelli d’età. Il problema principale nasce dalla mancanza di consapevolezza della natura delle teorie fisiche e del loro rapporto con l’esito degli esperimenti possibili. Discuteremo tale natura sia dal punto di vista epistemologico che da quello relativo alla didattica della disciplina e forniremo indicazioni per fondare su basi sempre più solide le ricostruzioni didattiche dei contenuti, per quanto riguarda la fisica moderna e anche per quello della fisica classica e, perciò stesso, per contribuire a creare le condizioni per una migliore didattica della fisica in generale

“The elegance of quantum mechanics”: An at-distance proposal for secondary school students

INTRODUCTION: THE STATE OF THE ART AND OPEN PROBLEMS Quantum Mechanics has been the focus of physics education research since the 90s and, nowadays, researchers no longer express doubts on the fact that it is fundamental for the culture and the awareness of the individual citizen and of the whole society (Redish, 2000; Besson, 2017). From surveys on teacher training (Stefanel, 2008; Fera, 2011; Giliberti, 2014; Krijtenburg-Lewerissa, 2017), it emerged that most teachers - mainly with a degree in mathematics - often do not have a coherent framework of modern physics in general, and of quantum physics in particular. Furthermore, the didactic path presented in textbooks is limited to a pseudo-historical presentation, which provides a hyper-simplified explanation of the fundamental concepts, in an attempt to bypass the problems associated with students’ lack of adequate mathematical tools, leading to deep misconceptions. OUR COURSE: “THE ELEGANCE OF QUANTUM MECHANICS” In this presentation we describe the work of designing, testing, and evaluating the effectiveness of a course entitled, “The elegance of quantum mechanics”, presented in Academy Year 2021/22. The activity - done online - was offered to teachers and students of the last three years of high school (120 participants overall), from October 2021 to January 2022, through weekly appointments of one and a half hours each. Lessons were integrated with slides, questions with Kahoot! and graphic examples with GeoGebra (https://www.geogebra.org/m/aqf2dgn3). Course effectiveness was assessed by collecting and analyzing different types of data deriving from an anonymous satisfaction survey, 9 Google Forms (given after each of the first nine lessons, with a total of 38 open questions and 24 exercises; for example: https://forms.gle/Nr2umPc53FCCi3KZ9), and 19 individual interviews, aimed at investigating strengths and criticalities. This analysis allowed us to identify the reasoning that students commonly use in facing some conceptual issues of quantum mechanics. The following will be discussed: strengths of the activity, regarding the mathematical aspects, the use of GeoGebra and Kahoot!; criticalities, especially in dealing with spaces with more than 3 dimensions, with the concept of self-adjoint operator, and concerning the confusion between states and operators; materials (https://pls.fisica.unimi.it/materiali/). A new course, implemented with the improvements mentioned above, is expected to start in October 2022. REFERENCES Besson, U. (2017). Didattica della fisica. Rome: Carocci Editore. Fera, G., Challapalli, S. R., Michelini, M., Santi, L., Stefanel, A., & Vercellati, A. (2011). Formare gli insegnanti all’innovazione didattica e all’orientamento, Connessi! Scenari di Innovazione nella Formazione e nella Comunicazione, 411-420. Giliberti, M. (2014). Theories as Crucial Aspects in Quantum Physics Education. Frontiers of Fundamental Physics and Physics Education Research. Springer Proceedings in Physics, vol 145. Springer, Cham. https://doi.org/10.1007/978-3-319-00297-2_51 Krijtenburg-Lewerissa, K., Pol, H.J., Brinkman, A., & Van Joolingen, W. R. (2017). Insights into teaching quantum mechanics in secondary and lower undergraduate education. Physical Review Physics Education Research, 13(1). Redish, E. F. (2000). Who needs to learn physics in the 21st century and why? Plenary lecture, GIREP Conference 2000. Stefanel, A. (2008). Impostazioni e percorsi per l’insegnamento della meccanica quantistica nella scuola secondaria. Giornale di Fisica 49, 15-53

“Good Vibrations”: A workshop on oscillations and normal modes

We describe some theatrical strategies adopted in a two hour workshop in order to show some meaningful experiments and the underlying useful ideas to describe a secondary school path on oscillations, that develops from harmonic motion to normal modes of oscillations, and makes extensive use of video analysis, data logging, slow motions and applet simulations. Theatre is an extremely useful tool to stimulate motivation starting from positive emotions. That is the reason why the theatrical approach to the presentation of physical themes has been explored by the group “Lo spettacolo della Fisica” (http://spettacolo.fisica.unimi.it) of the Physics Department of University of Milano for the last ten years (Carpineti et al., JCOM, 10 (2011) 1; Nuovo Cimento B, 121 (2006) 901) and has been inserted also in the European FP7 Project TEMI (Teaching Enquiry with Mysteries Incorporated, see http://teachingmysteries.eu/en) which involves 13 different partners coming from 11 European countries, among which the Italian (Milan) group. According to the TEMI guidelines, this workshop has a written script based on emotionally engaging activities of presenting mysteries to be solved while participants have been involved in nice experiments following the developed path