El artículo analiza el efecto de la resolución de problemas cualitativos mediante experimentos mentales, en el uso de la idea de conservación de la masa. Se trata de identificar los modelos expresados por los estudiantes y cómo estos se ajustan y autorregulan a partir del trabajo en el aula. Para ello se realiza un estudio de casos múltiples con estudiantes de secundaria obligatoria, empleando métodos cualitativos de análisis de datos. A lo largo del experimento mental, los estudiantes empezaron movilizando modelos ingenuos y simples, basados en la no conservación de la materia, y más de la mitad terminó formulando otros que integraban el principio de conservación de la masa y la idea de Tierra como sistema abierto. Ello sugiere el papel de los experimentos mentales como escenarios propicios para favorecer procesos de modelización en ciencias., This paper analyzes the effect of the resolution of qualitative problems through mental experiments, in the use of the idea of conservation of mass. Its purpose is to identify the models expressed by the students, and how they adjust and self-regulate as a result of the work in the classroom. For this, a multiple case study is carried out with secondary school students, using qualitative methods of data analysis. Throughout the mental experiment, students began mobilizing simple and naive models, based on a non-conservation of matter, while more than half ended up formulating others that spontaneously integrated the principle of conservation of mass and the idea of Earth as an open system. These results show the role of mental experiments as favorable scenarios for modeling in science.

A questionnaire was recently developed for the use with the Spanish-speaking, and evidence have been provided about the construct internal validity by means of structural equation modelling. In this paper, two research questions were considered: (i) What new evidence does application of the Rasch model provide regarding the validity of this construct? (ii) What cutoffs should be applied to the constructed scales in order to differentiate between acceptable and insufficient levels of the construct being measured? Participants were 1,272 Spanish at both high-school and college level. The instrument is a pencil and paper questionnaire written in Spanish, comprising 20 items (5-point Likert-type scale) distributed evenly across four scales: beyond exact replicas, purpose of models, multiple models, and changing models. Students’ responses were coded on an ordinal scale from zero to four. We then conducted a Rasch analysis using both a multidimensional approach and a consecutive unidimensional approach for each dimension. Data provided new evidence regarding the internal validity of the four scales of the questionnaire. The Rasch analysis also allowed us to establish cutoffs for the constructed scales. The evidence provided by this, and the previous study suggest that the questionnaire may be useful as a diagnostic tool when applied to groups or populations of students. In addition, the identified cutoffs could, hypothetically, serve to differentiate between students with an adequate versus an insufficient understanding of the nature of models., 18 páginas

The translation and adaptation of an assessment instrument into another language can be problematic, due, among other reasons, to sociocultural differences. This proved to be the case with the Spanish adaptation of the Students’ Understanding of Models in Science (SUMS) questionnaire, a Likert-type scale developed originally in English. In light of this, and with the additional aim of improving upon certain aspects of the original instrument, we report the development of a new questionnaire for assessing Spanish-speaking students’ understanding of the nature of models and their uses in science, providing validity evidence for the internal structure of the construct measured. The tool was developed by considering various dimensions of this concept that have been described in the literature, as well as the results of studies that piloted the SUMS questionnaire. For each dimension we drew up a set of items that could be rated using a Likert-type scale; half of these items were positively worded with respect to an adequate understanding of models, and half were reverse worded. The adequacy of the proposed items was first assessed by a panel of experts, following which we examined the score structure obtained with the resulting instrument by administering it to a sample of 1272 students aged between 14 and 55 years. After purifying the instrument based on the results of these analyses we obtained a final version of the questionnaire comprising 20 items distributed equally across four subscales: Beyond exact replicas, Purpose of models, Multiple models, and Changing models. The results obtained through factor analysis and structural equation modeling provide validity evidence for the internal structure of the construct measured. The questionnaire is quick to administer and is applicable to students across a wide range of ages and levels of education, including prospective science teachers., Funding information Spanish Ministry of Science, Innovation and Universities, Grant/Award Numbers: EDU2017-82197, EDU2017-82518-P, pp. 852-878

In this study, we analyzed the descriptive knowledge and mental models of the phenomenon of tides manifested by 111 preservice primary teachers. The instrument employed is an open-ended questionnaire, analyzed by means of an approach that explores the descriptions, explanations, and predictions in respect of this phenomenon by our subjects. First, we made a descriptive study of the kinds of ideas applied across different dimensions of analysis, and, subsequently, a cluster analysis was performed to check how those ideas were articulated and modeled. By means of this analysis, we were able to identify the mental models underlying the responses of preservice primary teachers. Furthermore, the results showed that the models they did have were not used when it came to making predictions in local situations. Instead, they employed heuristic rules based on everyday assumptions, not always consistent with tidal cycles of approximately 12 h. However, faced with situations that required thinking on a global scale, they did use their models, normally based on alternative conceptions. Lastly, from the results obtained, we consider some of the possible difficulties that preservice primary teachers may have in learning about the phenomenon of tides, and the implications for future teaching-learning designs aimed at overcoming those difficulties., Contract grant sponsor: Spanish Ministry of Science, Innovation, and Universities. R&D EDU2017-82518-P.

Este trabajo analiza la progresión del saber de futuros maestros de primaria en torno al modelo de ser vivo. El análisis se realiza a partir de los resultados de cuatro actividades incluidas dentro de una secuencia didáctica diseñada desde un enfoque de modelización en ciencias. Dos de ellas se basaban en un cuestionario administrado al inicio y final de la implementación en el aula, mientras las otras dos recopilaron información sobre el modelo de ser vivo consensuado en grupo al inicio y final de la propuesta. La comparación inicial-final permitió determinar en qué medida las ideas de los participantes progresaron a lo largo de la secuencia cursada. En general, los estudiantes experimentaron una mejora en el manejo de este modelo, tanto personalmente como en grupo, si bien no en todas las vertientes pueden considerarse satisfactorias. Ello muestra la conveniencia de cambios en la secuencia con vistas a futuras implementaciones., This work analyses the knowledge progression of future primary school teachers around the living being model. The analysis is carried out based on the results of four activities included in a didactic sequence designed from a science modelling approach. Two of them were based on a questionnaire administered at the beginning and end of the implementation in the classroom, while the other two collected information about the living being model done in group at the beginning and end of the proposal. The beginning-end comparison determined what extent the participants' ideas progressed throughout the course. In general, the students experienced an improvement in the management of this model, both personally and in groups, although not all aspects are considered satisfactory. This shows the need to change the sequence with a view to future implementations., 18 p.

Se presenta una secuencia didáctica diseñada para facilitar la comprensión del fenómeno de las mareas
e involucrar a los participantes en procesos de modelización. Esto implica la construcción, revisión y
reconstrucción de modelos, así como la reflexión en torno a su naturaleza y su papel en la enseñanza de la
ciencia. El objetivo de este artículo es describir y caracterizar dicha secuencia, así como su implementación en el
aula. Ésta sigue las pautas marcadas en las investigaciones de diseño: etapa preparatoria, etapa de implementación
de dos ciclos y estudio retrospectivo. Los resultados del estudio preparatorio reafirmaron las dificultades en la
enseñanza y aprendizaje de este tema: los profesores en las entrevistas mostraron su complejidad en diferentes
ámbitos; el análisis de los libros de texto detectó posibles mejoras escritas y visuales, y los cuestionarios previos
identificaron en los estudiantes ideas iniciales alejadas del modelo de ciencia escolar. En cuanto a la
implementación, la trayectoria de progresión propuesta resultó ser apropiada, al igual que la organización de las
actividades en el marco de la modelización. Además, se obtuvieron mejoras en los resultados del segundo ciclo de
implementación. Por último, el análisis retrospectivo conllevó la realización de dos grandes tipos de cambios en la
secuencia inicial y detectó una progresión en los modelos de la mayoría de los estudiantes., A didactic sequence designed to facilitate the understanding of the tides phenomenon and involve
participants in modeling processes is presented. This involves the construction, revision and reconstruction of
models, as well as reflection on their nature and their role in the teaching of science. The objective of this article
is to describe and characterize said sequence, as well as its implementation in the classroom. This one follows the
guidelines set by design based research: preparatory stage, two-cycle implantation stage, and retrospective study.
The results of the preparatory study reaffirmed the difficulties in teaching and learning this topic: the teachers in
the interviews showed its complexity in different areas, the analysis of the textbooks detected possible written
and visual improvements, and the previous questionnaires identified in the students’ initial ideas were far
removed from the school science model. Regarding implementation, the proposed progression trajectory turned
out to be appropriate, as was the organization of activities within the framework of modeling. In addition,
improvements were obtained in the results of the second implementation cycle. Finally, the retrospective analysis
involved the realization of two main types of changes in the initial sequence and detected a progression in the
models of most of the students., Financiado por: FEDER/Ministerio de Ciencia, Innovación y Universidades–Agencia Estatal de
Investigación/_Proyecto EDU2017-82518-P.

[Resumen] Modelo y modelización son términos empleados habitualmente con distintas acepciones en la enseñanza de las ciencias. En este artículo se analiza la dimensión instrumental de la modelización, identificándose distintos recursos y actividades de este tipo, como analogías, metáforas, personificaciones, maquetas, experimentos mentales, simulaciones, etc. Además, se revisan algunas aportaciones procedentes de la literatura sobre investigación en este ámbito, proporcionando ejemplos de estudios realizados y del tipo de metodología de investigación usada a lo largo de los mismos. Finalmente se formulan distintas conclusiones obtenidas en el conjunto de publicaciones realizadas y se sugieren algunos interrogantes y líneas de trabajo que quedan por cubrir en este marco., [Abstract] The terms model and modelling are commonly used with different meanings in science education. This paper analyses the instrumental dimension of modelling and identifies different modelling resources and activities, such as analogies, metaphors, embodiments, mock-ups, thought experiments, simulations, etc. The paper also reviews contributions from the literature in this area, including the different kinds of studies conducted, research methodologies used and conclusions obtained. The paper concludes by identifying a series of questions and new lines of research that remain to be explored., Financiado por: FEDER/Ministerio de Ciencia, Innovación y Universidades-Agencia Estatal de Investigación/_Proyecto EDU2017-82518-P