Contribution to a talk in a thematic conference: Physics Education

Contribution to a talk in a thematic conference: Physics Education
Upper secondary students face optic diffraction using simple experiments and on-line
measurements
Marisa Michelini, Lorenzo Santi, Alberto Stefanel
RESEARCH UNIT IN PHYSICS EDUCATION, DCFA OF THE UNIVERSITY OF UDINE
[email protected], [email protected], [email protected]
The phenomenon of optical diffraction is crucial in order to recognize the wave behavior of light. It limits the
resolving power of optical instruments, including the human eye. Therefore it is of fundamental importance
not only for practical applications, for example as in microscopy, but also in ability of our eye to distinguish
two objects, as well as in our perception of one colors next to another, aspect exploited for example by
Pointillists painters.
The exploration of the optical diffraction in teaching laboratory with on-line sensors offers a unique
opportunity to high school students to have experience of this important phenomenological context. Activities
of computer modeling allow to pass from phenomenology to its interpretation.
A research-based path was developed for upper secondary school approaching the optical diffraction
through the experimental exploration of the diffraction pattern produced by a laser beam incident on a single
slit. Students first analyze the diffraction pattern qualitatively, recognizing the global properties, , then
measuring with on-line sensors the light intensity vs position, constructing empirical relations between order
and position of minimum, order and position of maximum, position and intensity of maximum. A computer
modeling, based on Huygens' principle, is used to fit experimental data, showing the empirical relations,
characterizing the experimental distribution and that obtained with the model..
Experiments in school was performed with 85 students, using IBL tutorial worksheets e pre-test, post-test.
Positive learning paths of students emerged concerning: the role of diffraction in everyday situations,
activated by the qualitative analysis of the global properties of the diffraction pattern.
The characteristic of the diffraction pattern, explored with on-line sensors, combined with the modeling
activities aided students to move from a geometric point of view, based on rectilinear rays, to a physical one,
based on an interference / intensity analysis.
Italinglish
Il fenomeno della diffrazione ottica è cruciale in order to recognize the wave behavior of light. Esso limita il potere
risolutivo degli strumenti ottici, incluso l’occhio umano. Pertanto esso è di fondamentale importanza non solo per
applicazioni pratiche ad esempio in microscopia, ma anche nella nostra capacità di distinguere visivamente due oggetti,
come pure nella nostra percezione dei colori accostati l’uno all’altro, aspetto sfruttato ad esempio dai pittori puntinisti.
L’esplorazione della diffrazione ottica in laboratorio didattico con sensori on-line offre la possibilità anche a studenti di
scuola superiore di avere esperienza di questo importante contesto fenomenologico. Attività di modellizzazione al
computer permettono di passare della fenomenologia all’interpretazione dei fenomeni.
A research-based path was developed for upper secondary school approaching optical diffraction through the
experimental exploration of the diffraction pattern produced by a laser beam incident on a single slit. Students analyze
the diffraction pattern first qualitatively, recognizing the global properties, then measuring with on-line sensors the light
intensity vs position, constructing empirical relations between order and position of minima, order and position of
maximum, position and intensity of maximum. A computer modeling, based on Huygens principle, is used to fit
experimental data, showing that the empirical relations obtained caratterizzano sia la distribuzione sperimentale, sia
quella ottenuta con il modello.
Experiments in school was performed with 85 students, using IBL tutorial worksheets e pre-test, post-test. Positive
learning paths of students emerged concerning: the role of diffraction in everyday situations, activated by the qualitative
analysis of the global properties of the diffraction pattern.
The characteristic of the diffraction pattern, esplorata con sensori on-line, combinata con l’attività di modellizzazione
aided students to move from a geometric point of view, based on rectilinear rays, to a physical one, based on an
interference/intensity analysis.
Contribution to a talk in a thematic conference: Physics Education :
Teaching modern physics in secondary school
Mariza Michelini, Lorenzo Santi, Alberto Stefanel
RESEARCH UNIT IN PHYSICS EDUCATION, DCFA OF THE UNIVERSITY OF UDINE
[email protected], [email protected], [email protected]
The physics of the 900 introduced profound changes in theoretical paradigms of reference, such
as those of relativity and quantum mechanics even more. New areas were opened for
phenomenological research, such as superconductivity or quantum electronics.
At the same time, classical physics has found new areas of application in the techniques of
materials characterization, based on the principles of physics such as optics,
electromagnetism. Semiclassical models are widely used at various levels in the research that
use these techniques of analysis.
At the beginning of the third millennium it is becoming increasingly urgent to introduce in
school curricula all four of these dimensions of physics of XX century.
In the experience of the PERG of the University of Udine have been developed and tested with
high school students some specific educational proposals in each of the different dimensions.
A trail on the base principles of quantum mechanics aims at the construction of theoretical
thinking, engaging students in a explorative palextra of experiments and simulations in the
challenge of interpreting the phenomenology of a specific context (the optical polarization)
in the light of the quantum nature of matter and radiation.
An educational path of phenomenological exploration of superconductivity offers the
interpretive challenge to give account for the ideal properties of superconductors and tie
into a single theoretical framework, the electrical transport properties and the magnetic
properties of superconductors.
The experimental research carried out on the basis of these innovative proposals led to
understand which learning paths students follow in addressing physics 900.
Italiano
La fisica del ‘900 ha introdotto profondi cambiamenti nei paradigmi teorici di riferimento,
come quelli della relatività e ancor più della meccanica quantistica. Nuovi ambiti
fenomenologici si sono aperti per la ricerca, come ad esempio la superconduttività o
l’elettronica quantistica.
Al tempo stesso, la fisica classica ha trovato nuovi ambiti di applicazione nelle tecniche di
caratterizzazione dei materiali, basate sui principi fisici ad esempio dell’ottica,
dell’elettromagnetismo. Modelli semiclassici vengono ampiamente impiegati a vari livelli nelle
ricerche che proprio utilizzano tali tecniche di analisi.
All’inizio del terzo millennio appare sempre più urgente introdurre nei curricola scolastici
tutti e quattro queste dimensioni della fisica del ‘900.
Nella esperienza del PERG dell’Università di Udine sono state messe a punto e sperimentate con
studenti di scuola superiore alcune specifiche proposte didattiche in ciascuna delle
differenti dimensioni.
Un percorso didattico sui principi fondanti della meccanica quantistica mira alla costruzione
del pensiero teoretico, coinvolgendo gli studenti in una palestra di esplorazioni sperimentali
e in laboratorio simulato nella sfida interpretativa di analizzate uno specifico contesto
fenomenologico (la polarizzazione ottica), alla luce della natura quantistica della materia e
della radiazione.
Un percorso di esplorazione fenomenologica sulla superconduttività propone la sfida
interpretativa di rendere conto delle proprietà ideali dei superconduttori e di legare in un
unico quadro teorico le proprietà di trasporto elettrico e le proprietà magnetiche dei
superconduttori.
Differenziate proposte sulle tecnicbe di caratterizzaione dei materiali sono state messe a
punto ad esempio per quello che riguarda la Rutherford Backsattering Spettroscopy e la Time
Resolved Reflectivity, L’utilizzo di modelli semiclassici è alla base dell’interpretzione di
tali esperimenti, come pure degli esperimenti cruciali che hanno portato alla nascita della
fisica del ‘900.
Le sperimentazioni di ricerca effettuate sulla base di tali proposte innovative hanno portato
a comprendere quali percorsi di apprendimento gli studenti seguono nell’approcciarsi alla
fisica del ‘900.
Contribution to a poster : Conceptual Labs for operative Exploration
Marisa Michelini, Alberto Stefanel, Lore zo Santi
Research Unit in Physics Education, University of the University of Udine
In the perspective of the Model of educational reconstruction, designing new educational path require to
gain new information on how students face the specific subject explored.
At the PERG of Udine the main steps of the new educational paths were explored with pupils engaged in
Conceptual Laboratory of Operative Exploration (CLOE) in informal learning contexts, where using different
monitoring tools student spontaneous ideas as well their learning path were explored and stimulated. .
In CLOE pupils discuss everyday life scenarios, recover their everyday and sensorial knowledge, as well as
involve them in the challenges of explorations according to an IBL strategies.
The CLOE lab are research based proposals of learning where explore how pupils build formal thinking,
reflect on phenomena and construct models, reinterpret common everyday knowledge. The research focus
is on the reasoning sequence, the ways in which knowledge is structured, the development of
interpretative representations. The design characteristic of the CLOE labs are presented exemplifying it in
the case of the CLOE on energy .
Vecchio Abstract
Conceptions of secondary students on phenomenology of superconduction
Mariza Michelini, Lorenzo Santi, Alberto Stefanel
RESEARCH UNIT IN PHYSICS EDUCATION, DCFA OF THE UNIVERSITY OF UDINE
[email protected], [email protected], [email protected]
Currently , superconductors at low cost can be used to analyze the typical
superconducting phenomena in schools.
Experimental problem solving on Meissner levitation and breackdown of the resistivity of
the superconductors at phase transition for the exploration of the ideal properties of a
conductor have been proposed to students of Italian secondary schools, with the use of
worksheets tutorials that implement inquiry based learning strategies.
The students' initial conceptions about how an ideal conductor dynamically interacts
with a magnet in motion, as these conceptions are modified by the phenomenological
exploration and how they are structured at the end of the learning path were monitored
with pre-test, post-test focused on conceptual issues explored experimentally.
The results evidence that students initially believe that an ideal conductor is a
transparent medium to the magnetic field. The explotion of analogical situations of
suspension and deceleration of magnets activate in students the recognition of the
nature of ideal diamagnet of a superconductor
Attualmente, superconduttori a basso costo possono essere utilizzati per analizzare i
tipici fenomeni superconduttivi anche nelle scuole. Problem solving sperimentali sulla
levitazione Meissner e il breackdown della resistività di superconduttori alla
transizione di fase per l'esplorazione delle proprietà di conduttori e diamagneti ideali
dei superconduttori sono state proposte a studenti di scuole secondarie italiane, con
l'uso di worksheet tutorials che implementano strategie di tipo inquiry based learning.
Le concezioni iniziali degli studenti su come un condutttore ideale interagisce
dinamicamente con un magnete in moto, come esse vengono modificate dalla esplorazione
fenomenologica e come si strutturano al termine dei percorsi di aprendimento sono stati
monitorati con pre-test, post-test focalizzato sui nodi concettuali esploati
sperimentalmente.
The results evidence that students ritengono inizialmente che un conduttore ideale è un
mezzo trasparente al campo magnetico. L'esplotazioni di situazioni analogiche di
sospensione e frenamento di magneti attivano il riconoscimento della natura di
diamagnete ideale di un superconduttore.
Currently , superconductors at low cost can be used to analyze the typical
superconducting phenomena in schools.
Experimental problem solving on Meissner levitation and breackdown of the resistivity of
the superconductors at phase transition for the exploration of the ideal properties of a
conductor have been proposed to students of Italian secondary schools, with the use of
worksheets tutorials that implement inquiry based learning strategies.
The students' initial conceptions about how an ideal conductor dynamically interacts
with a magnet in motion, as these conceptions are modified by the phenomenological
exploration and how they are structured at the end of the learning path were monitored
with pre-test, post-test focused on conceptual issues explored experimentally.
The results evidence that students initially believe that an ideal conductor is a
transparent medium to the magnetic field. The explotion of analogical situations of
suspension and deceleration of magnets activate in students the recognition of the
nature of ideal diamagnet of a superconductor
Thanks to the ideal properties of Superconductors are ideal conductor and A research
based educational path on superconductivity was designed for secondary school students,
adopting an inquiry based approach to the phenomenology of Meissner effect. The perfect
diamagnetic property of a superconductor is correlated to the his null resistivity
through the recognition of the role of electromagnetic induction in the superconductive
state. A qualitative introduction of the Cooper pairs formation and correlate gap in
superconductor energy levels is proposed to the students to interpret the phenomenology.
Research experimentation was carried out using tutorial worksheet with Italian secondary
school students to explore how it is possible to introduce superconductivity using a
phenomenological approach, the students main difficulties and their typical learning
paths. Data was collected from worksheets and questionnaires. The results evidence that
students are able to describe the null B field and the null resistivity situation in a
superconductor using different formal tools.