Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

El presente trabajo aborda la descripción y fundamentación, desde el punto de vista teórico-metodológico, del diseño de un libro de texto universitario de análisis instrumental de los alimentos. Para ello, se tomaron en consideración los postulados del enfoque histórico-cultural y la teoría de la actividad, situando el centro de atención en la tarea docente-educativa como elemento integrador del sistema de contenidos. La concepción didáctica para el diseño de la propuesta se apoyó en otros aspectos relevantes, como el enfoque profesional de los contenidos, el diseño de un efectivo aparato de organización de la asimilación y, por último, la funcionalidad y pertinencia del material ilustrativo. Una muestra conformada por estudiantes de tres cursos académicos diferentes refirió una percepción muy positiva sobre la contribución del libro a la comprensión de los contenidos de la asignatura.

This study aimed to uncover students scientific and unscientific understanding of the topic of acid-base properties of salt solution. This descriptive study involved 300 students covering three public secondary schools in Malang, East Java, Indonesia. The four-tier instrument in the topic developed and found valid from our previous work was employed for data collection. It is found that students' scientific understanding of some concepts is strong. However, some unscientific understanding were also uncovered. The implication for teaching the topic is also discussed.

Las nuevas generaciones de la Era Digital tienen un lenguaje y manera de comunicarse interactivo y ágil. Es importante innovar en los métodos de enseñanza, y aprovechar las capacidades y habilidades que ellos poseen. El objetivo de este trabajo fue desarrollar una plataforma interactiva, implementada como sitio web , que pueda ser utilizada por estudiantes universitarios del área de la ingeniería y ciencias, para aprender la estequiometría de las reacciones, y comprender las estructuras de las moléculas químicas, mediante impresión 3D. La metodología consistió en dos trabajos principales: 1) el desarrollo de un software interactivo para formular reacciones químicas equilibradas, en formato para sitio web, y 2) el diseño en 3D de moléculas. Las moléculas fueron diseñadas de manera de ser autoexplicativas, utilizando como base moléculas diseñadas en el sitio web de libre uso MolView, y otras utilizando la Teoría de Repulsión de Pares de Electrones de Valencia (TREPEV). Se logró desarrollar una plataforma interactiva llamada “Química 3D”, en la cual se podrán formular todas las reacciones posibles, el estudiante ingresará los reactantes y productos de la reacción, y mediante un algoritmo se generarán tres alternativas de coeficientes estequiométricos, con una alternativa correcta. El estudiante debe escoger la alternativa correcta, para tener acceso para visualizar las moléculas en imagen con diseño 3D, y además descargar el archivo para impresora 3D Makerbot, y de esta manera comprender su geometría espacial y estructura.

The present research investigates the mental models about the atom of Spanish 15- to 18- years old students. A sample of 454 students was taken into account within a representative Spanish context. A specific questionnaire, validated before students solved it, where the students should draw, define and argue was designed. It has been found that most of the students understand the atom as a mix of several models. In general, the models they mix are those that they studied during their last educational course. Some students possess a unique mental model about the atom (Bohr´s model), and a really few students described the atom as it could be expected according to their educational level. Several reasons have been appointed among them are: i) the construction of a mental model is a hard and slow process, even more in the case of the atom, ii) this is a complex concept which requires abstraction and to use spatial knowledge in very young students, and iii) teachers offer to students few situations to check their mental models, and thus, it takes so much time to find the strengths and weaknesses of their models.

The research of misconceptions focuses on identification, prevention, and elimination. Misconceptions are more commonly identified and eliminated than prevented. Elimination of misconceptions tends to be ineffective because misconceptions tend to be resistant. Therefore, preventing misconceptions is a better option than eliminating misconceptions. This article reviewed some literature to design the preventing misconceptions learning. The construction is based on an analysis of effective chemical learning strategies implemented to overcome misconceptions. Learning expected can prevent chemical misconceptions includes four components: (1) improving formal thinking ability; (2) emphasizing concepts constructed by students fundamentally; (3) involving chemical representation; and (4) developing students' positive attitudes towards chemistry. The closest learning approach to preventing misconceptions is guided-inquiry oriented learning. However, there are no stages in the inquiry learning phase detecting the misconceptions before they are applied. The students who have misconceptions can revise them during the concept validation stage. Students can apply valid concepts constructed during the application and problem-solving stages. So, the learning stages designed for preventing misconceptions are (1) Exploration; (2) Concept construction; (3) Concept Validation; (4) Concept Application; and (5) Problem-solving.

In this article, we present the analysis of a problem-solving activity performed during a chemical technician course. We examine the contributions of the teaching-learning sequence when implemented in the development of conceptual, procedural, and attitudinal learning, focusing on environmental issues related to pesticides. In our investigation, we also report the perception of students regarding the teaching-learning sequence. The research was carried out in a public school in the city of Porto Alegre, Brazil, involving 29 students of the chemical technician course. The students solved problems created to address different approaches concerning pesticides. Data were obtained by the analysis of the researchers’ field diaries and questionnaires of the class in which the students participated in the problem-solving activity. The results showed that the teaching-learning sequence favoured conceptual, procedural, and attitudinal learning related to problem-solving and the environmental hazards that pesticides can cause. It was observed that the problem-solving methodology favoured the students’ autonomy, which is the ability to self-govern, to make one’s own decisions, and to be critical and reflective.

En este documento se da a conocer la importancia de los semiconductores orgánicos en la fabricación de dispositivos optoelectrónicos, se abordan algunos conceptos fundamentales acerca de la estructura molecular los cuales deben ser considerados en el diseño de la molécula semiconductora. Se resaltan, ventajas y desventajas de los semiconductores orgánicos frente a los semiconductores inorgánicos. Para comprender la relación estructura-propiedades de este tipo de moléculas se presentan los conceptos básicos acerca de la electrónica orgánica, la importancia de la ingeniería del band gap (Eg); así como el funcionamiento, características fisicoquímicas, propiedades optoelectrónicas y aplicaciones de celdas solares orgánicas (OPVs y DSSC), Diodos Orgánicos Emisores de Luz (OLEDs) y Transistores Orgánicos de Efecto de Campo (OFETs).

The development of electrochemical sensors capable of quantifying either chemical, biological, or environmental parameters of interest endorses both the increased academic and educational relevance of electrochemistry. As a result, understanding quantitative electrochemical sensing characterization and performance analysis through analytical figures of merit stands as a curricular requirement from both a theoretical and methodological standpoint as it involves the development of several skills which are highly transferable into further electrochemical education and professional practices. On the other hand, due to popular fields of applications such as non-invasive wearable electrochemical sensors for monitoring electrolytes in sweat on high-performance athletes, students are well-aware of its potential, increasing their willingness to partake in electrochemical activities. Addressing the aforementioned, the experience described herein is divided into two main sections. Firstly, a theoretical introduction regarding electrochemical sensors and electrochemical performance validation techniques known as electroanalytical figures of merit are proposed. Secondly, a hands-on experience using a H2O2sensitive ferrite powder working electrode is carried out by performing voltammetric and chronoamperometric techniques so that students develop a basic understanding of the redox processes occurring at the working electrode surface and obtain analytical performance parameters that allow conclusions to be drawn regarding the ferrite powder sensing capabilities towards H2O2 reduction. As for implementation requirements, the proposed four-hour laboratory protocol is suitable for graduate/upper-level undergraduate physical or analytical chemistry courses and, due to its length, is recommended to be conducted in groups of two to three students.

La enseñanza no formal proporciona cada vez más recursos con los que satisfacer las necesidades tanto de profesores como de alumnos. Sin embargo, la atención dirigida por la investigación a estos contextos ha sido reducida y, quizá por ello, su potencial no está del todo explotado. Por este motivo, es imprescindible conocer qué necesita el profesorado de estos espacios y qué espera de ellos.En el presente trabajo se ha indagado en las razones que llevan al profesorado de secundaria a participar en una actividad científica no formal como es el Concurso de Cristalización en la Escuela. El análisis de las respuestas ofrecidas por los docentes a un cuestionario de preguntas abiertas ha revelado la presencian de siete grandes categorías de respuesta que agrupan una gran variedad de motivos.Estos resultados amplían los recogidos en la bibliografía y además proporcionan un marco que permite interpretar las creencias del profesorado y comprender en mayor profundidad los motivos por los cuales deciden participar en actividades no formales. Por último, también remarcan las características del concurso mejor valoradas por los educadores permitiendo concluir que los docentes perciben el concurso como una experiencia muy enriquecedora y una herramienta formativa de lo más completa.

The COVID-19 pandemic has brought substantial changes in ways of life; and education as a fundamental part of cultural transformation has not been left out of the maelstrom of adaptations to new ways of life. The present work proposes the readjustment of the academic management of the Faculty of Chemical Sciences of the National University of Asunción (FCQ-UNA), through the creation of the Virtual Classroom 2020 as an integrating platform that allowed the continuity of the academic processes of the seven careers offered only in presence-based modality. For its proper execution, trainings have been carried out for teachers and students, which have been addressed with the objective of achieving digital skills in virtual teaching-learning environments. A survey of the teachers’ perceptions about the implemented mode was carried out, the results of which are presented in the paper, to report the effectiveness of the system for the achievement of the objectives. The results indicate a high satisfaction of the teachers about the implemented strategies, which have served to give a new, more dynamic, and open approach to their classes, both in theory and in laboratory practices and problem solving.