1,721,013 research outputs found
Dal diapason al Sole: una proposta innovativa per l'insegnamento delle onde meccaniche
No full textIn questo lavoro presentiamo un modulo innovativo che ha lo scopo di affrontare le piu comuni misconcezioni degli studenti riguardo le onde meccaniche, attraverso la fusione di un contesto tradizionale quale lo studio del suono di un diapason con uno insolito quale lo studio del suono prodotto dal Sole. Gli studenti, utilizzando un software audio digitale, determinano la frequenza fondamentale di un diapason e quindi la frequenza fondamentale delle oscillazioni del Sole. Inoltre viene mostrato come in Fisica si possa utilizzare la stessa tecnica (analisi spettrale) per ottenere informazioni riguardo fenomeni fisici molto diversi. Il modulo e stato proposto in via sperimentale nell'anno scolastico 2014-2015 durante il Piano Lauree Scientiche - Fisica presso l'Universitàa di Napoli a circa 40 studenti frequentanti la classe quarta di Liceo Scientico. Questa sperimentazione sarà il punto di partenza per la realizzazione di uno strumento di valutazione finalizzato ad indagare l'efficacia delle attivitàa presenti nel modulo
Teaching about mechanical waves and sound with a tuning fork and the Sun
Get PDFLiterature in Physics Education has shown that students encounter many difficulties in understanding wave propagation. Such difficulties lead to misconceptions also in understanding sound, often used as context to teach wave propagation. To address these issues, we present in this paper a module in which the students are engaged in computer-based activities dealing with sounds produced by a tuning fork and the Sun. The main reason underlying such choice is to show how the same measurement technique (spectral analysis) can be used to obtain information about very different phenomena. The activities build on a formal analogy to determine the fundamental frequency of sounds emitted by the two sources (tuning fork and Sun). Using a digital audio editor, the sounds are analyzed using three types of graphs: intensity versus time (waveform), intensity versus frequency (spectrum), and frequency versus time (spectrogram). The aim of the activities is to address students' alternative conceptions about the frequency and propagation of mechanical waves using a multi-representation of the same phenomenon. Examples of frequency measurements for the analyzed sounds are reported, as well as paper-and-pencil tasks to determine velocity of sound in the two phenomena. Implications for the teaching of waves and sound are finally discussed
Development and validation of a learning progression for change of seasons, solar and lunar eclipses, and moon phases.
Get PDFIn this paper, we report about the development and validation of a learning progression about the Celestial Motion big idea. Existing curricula, research studies on alternative conceptions about these phenomena, and students’ answers to an open questionnaire were the starting point to develop initial learning progressions about change of seasons, solar and lunar eclipses, and Moon phases; then, a two-tier multiple choice questionnaire was designed to validate and improve them. The questionnaire was submitted to about 300 secondary students of different school levels (14 to 18 years old). Item response analysis and curve integral method were used to revise the hypothesized learning progressions. Findings support that spatial reasoning is a key cognitive factor for building an explanatory framework for the Celestial Motion big idea, but also suggest that causal reasoning based on physics mechanisms underlying the phenomena, as light flux laws or energy transfers, may significantly impact a students’ understanding. As an implication of the study, we propose that the teaching of the three discussed astronomy phenomena should follow a single teaching-learning path along the following sequence: (i) emphasize from the beginning the geometrical aspects of the Sun-Moon-Earth system motion; (ii) clarify consequences of the motion of the Sun-Moon-Earth system, as the changing solar radiation flow on the surface of Earth during the revolution around the Sun; (iii) help students moving between different reference systems (Earth and space observer’s perspective) to understand how Earth’s rotation and revolution can change the appearance of the Sun and Moon. Instructional and methodological implications are also briefly discussed
A teaching module about stellar structure and evolution
No full textIn this paper, we present a teaching module about stellar structure, functioning and evolution. Drawing from literature in astronomy education, we designed the activities around three key ideas: spectral analysis, mechanical and thermal equilibrium, energy and nuclear reactions. The module is divided into four phases, in which the key ideas for describing stars' functioning and physical mechanisms are gradually introduced. The activities (20 hours) build on previously learned laws in mechanics, thermodynamics, and electromagnetism and help students combine them meaningfully in order to get a complete picture of processes that happens in stars.
The module was piloted with two intact classes of secondary school students (N = 59 students, 17–18 years old), using a ten-question multiple-choice questionnaire as research instrument. Results support the effectiveness of the proposed activities. Implications for the teaching of advanced physics topics using stars as fruitful context are briefly discussed
Design and Development of a Learning Progression about Stellar Structure and Evolution
Get PDFIn this paper, we discuss the design and development of a Learning Progression (LP) to describe and
interpret students’ understanding about Stellar Structure and Evolution (SSE). The LP is built upon three
content dimensions: hydrostatic equilibrium; composition and aggregation state; functioning and
evolution. The data to build up the levels of the hypothetical LP (LP1) came from a 45-minute, sevenquestion
interview, with 33 high school students previously taught about the topic. The questions were
adapted from an existing multiple-choice instrument. Data were analyzed using Minstrell’s “facets”
approach. To assess the validity of LP1, we designed a twelve-hour teaching module featuring paper-andpencil
tasks and practical activities to estimate the Stellar Structure and Evolution parameters. Twenty high
school students were interviewed before and after the activities using the same interview protocol. Results
informed a revision of LP1 (LP2) and, in parallel, of the module. The revised module included
supplementary activities corresponding to changes made to LP1. We then assessed LP2 with 30 high school
students through the same interview, submitted before and after the teaching intervention. A final version
of the LP (LP3) was then developed drawing on students’ emerging reasoning strategies. This paper
contributes to research in science education by providing an example of the iterative development of the
instruction required to support the student thinking that LPs’ levels describe. Concerning astronomy
education research, our findings can inform suitable instructional activities more responsive to students’
reasoning strategies about Stellar Structure and Evolution
Developing the use of visual representations to explain basic astronomy phenomena
Get PDFSeveral decades of research have contributed to our understanding of students’ reasoning about astronomical phenomena. Some authors have pointed out the difficulty in reading and interpreting images used in school textbooks as factors that may justify the persistence of misconceptions. However, only a few studies have investigated to what extent usual textbook images influence students’ understanding of such phenomena. This study examines this issue exploring 13-14 years old students’ explanations, drawings and conceptions about three familiar phenomena: change of seasons, Moon phases and solar/lunar eclipses. The research questions that guided the study were: RQ1) How are students’ explanations and visual representations about familiar astronomical phenomena affected by different imagesupport conditions? RQ2) How are students’ conceptions about familiar astronomical phenomena affected by different image-support conditions? RQ3) Which features of the used images most affected the students’ visual representations and explanations of familiar astronomical phenomena? To answer our research questions, we designed three instructional contexts under increasing support conditions: textbook images and text; teaching booklets with specially designed images and text; only text. To analyze students’ drawings, we used exploratory factor analysis to deconstruct drawings into their most salient elements. To analyze students’ explanations, we adopted a constant comparison method identifying different levels of increasing knowledge. To investigate students’ conceptions, we used a mixed multiple choice/true false baseline questionnaire. For RQ1, results show that the specially designed images condition was effective in helping students producing informed drawings in comparison to text-only condition for all phenomena, and more effective than textbook images condition when one considers seasonal change drawings. Concerning RQ2, the specially designed images condition was the most effective for all phenomena. Concerning RQ3, prevalent elements of astronomy images that affected students’ explanations and visual representations were: elliptical Earth's orbit, position of the Sun with respect to the Moon orbit, Sun, Moon and Earth alignment. Our findings confirm concerns about textbook astronomy images, whose features may interfere with the identification of the relevant factors underlying the phenomena. Moreover, findings of this study suggest that affordances of the specially designed images may play an essential role in scaffolding meaningful understanding of the targeted phenomena. Implications for teaching through and learning from visual representations in astronomy education are briefly discussed
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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