Educacion Quimica最新文献

College students show serious difficulties in learning chemistry. From research in science teaching, this problem is considered to be multicausal. We will focus on one of the possible intrinsically disciplinary causes. Among the first issues addressed in basic chemistry courses of scientific/technological careers are those corresponding to quantum chemistry. When the student approaches for the first time these subjects only knows classic contents of physics and chemistry. While many of the terms used in both contexts are the same, the ‘world’ and ‘objects’ referred to in classical physics not seem to be the same that those that is cited in chemistry. The fact that it would seem that the quantum chemistry depends on physical models available of the world, it adds the complication of using classical physics concepts in a context in which they no longer seem to have the same meaning. In this paper we analyze the way in which general chemistry textbook introduced the contents of quantum chemistry. Four aspects are considered: epistemologic choice, perspective of approach, use of the history and philosophy of science, and contextualisation of relations between quantum and classical concepts. We conclude that the modes of presentation in the texts do not contribute to a better understanding of the concepts of the discipline, nor of the mode in which the scientific knowledge is developed.

A common problem associated with having General Chemistry students view animations is that students tend to accept the animations as “correct” explanations without question or consideration for their limitations. This study proposes a new strategy for presenting animations in chemistry instruction that requires students to critique contrasting animations to determine which animation is a best fit with video-recorded scientific evidence. The purpose of the study was to examine how undergraduate students, enrolled in their first semester of a General Chemistry course, responded to two contrasting animations, one that was scientifically accurate and one that was scientifically inaccurate, as molecular level explanations of a video of a redox reaction involving the reaction between solid copper and aqueous silver nitrate. An analysis of a metacognitive monitoring activity was performed to study how students saw similarities and differences between the animations, as well as, to their own molecular level explanations of the reaction event. The findings revealed that students picked up on the mechanistic differences between the animations, but they struggled with understanding why the reaction happened. Regardless of their background knowledge of chemistry, students voiced preference for animations that were simplistic in their appearance and obvious in what they conveyed while also having an explicit connection to the macroscopic level.

This paper presents a didactic approach for initial science teacher education on the nature of science (NDC) using the history of science (HDC). This approach is developed through a reflective reading of stories about cases and controversies from HDC, which has been made by the authors of this work. A brief description of the stories and the methodological strategy for its implementation in the classroom are included. Also, the qualitative assessment of the participants’ reflections through a rubric with levels of progression is described.

This work shows the results of a learning experience on acid-base titrations, based on the projection of a simulation, in the context of an integrating and conceptual final evaluation. This activity was done after the first year university students attended theoretical, problem-solving and lab lessons and were subjected to traditional evaluation. Students were inquired about how they had identified the different materials and entities shown in the simulation and how they had established adequate conceptual links between them. In order to evaluate the results, the sample was divided in two groups depending on whether the participants had approved or not the General Chemistry mid-term evaluation. Interesting conclusions came up about what happens when students have to draw information from a simulation to solve traditional format problems.

Due to the “big five” challenges in the 21st Century related to the terms of energy, food, water, mobility and climate, mankind has to replace energy from fossil fuels step by step by renewable energies. Between them, solar energy is definitely the most abundant and clean. This is a major, but not the only reason for the inclusion of photoprocesses into chemical education. In this article we present an experimental approach to the basic concept suitable for teaching all phenomena involving light in a reasonable approximation. Updated experiments demonstrating the down conversion of light by fluorescence and room-temperature phosphorescence as well as aggregation induced emission and rigidification induced luminescence are described. In order to use these experiments for teaching basic concepts in photochemistry, a simple version of an energy level model, and an extended version, containing vibrational states, are proposed.

This paper discuss one recent episode in the history of chemistry which currently has received little attention in the scientific realism debate: the rise and “apparent” fall of an approximate model of the chemical bond known as Linnett double-quartet theory. In 1961 Linnett published a paper in the Journal of the American Chemical Society entitled “A Modification of the Lewis-Langmuir Octet Rule” in which he suggested certain changes in G. N. Lewis's original views on the role of the electron pair in covalent bond formation based on an explicit consideration of the effects of electron spin – a property of the electron unknown to Lewis in 1916. Although his theory produced outstanding predictions, it is now forgotten.

Electrochemical silver is an interesting activity of teaching for the integration of electrochemistry, chemistry, physics and art. Craftsman needs to produce a bright layer of silver on his works and so chooses to use electrolyte of diverse nature. The cost and the degree of toxicity are two important variables that have an impact on the determination of the choice of the electrolyte to be used. Silver usually is find in the complex state and the study of the different complexes represents an interesting activity in the chemistry of coordination compounds. It is important to establish a relation between the brightness of the coating and the stability of the complex compound of silver and therefore of its structure. This paper correlates characteristics of electrolyte with the silver brightness electrochemically deposited on copper and nickel. In order to quantify the silver brightness, the reflectivity measurements were made with the luxmeter.

Chemistry education is now increasingly seen as an academic field of scholarship in its own right. This article suggests two important principles to be taken into account when considering the question ‘What should be the key foci for chemistry education research (CER)?’. The first of these applies a typology that divides research into chemistry classrooms as inherent (‘essential’), embedded (‘entangled’) or collateral (‘incidental’), according to the extent to which the research is conceptualised in terms of issues that arise in teaching and learning the specific subject matter of chemistry. It is important for the development of the field that inherent CER is particularly encouraged. The second principle relates to what makes a field scientific. Here it is suggested that research needs to have a programmatic nature so that the field does not just accumulate more studies, but is seen to progress by allowing new researchers to effectively be inducted and then build upon existing work.

Today, molecular viewers are an undeniable reality in the classroom. This type of softwares allow students the three dimensional development. In this study, free access molecular viewer Avogadro was used. The using of the program was successful not only in the three dimensional training, but in the pointing out of carbons’ quilarity of optical isomers. In fact, the velocity was reduced to a half part in comparison to bidimensional molecules. On the other hand, students were prone to the usage of Avogadro in basic and advanced chemical courses.

Currently, it is evident the need of discussing the curricular orientation that Material Science should have as a key subject in undergraduate programs of science, engineering and related careers with technological and industrial design applications. In this work, some fundamental aspects for building of Materials Science curricula are discussed from scientific, technological and pedagogical perspectives. A scientific and technological view allows establishing conceptual contents intended from world modern knowledge on research and technological activities performed for Materials and Solid State fields. The pedagogical view shows that meaningful learning and STS (Science, Technology and Society) approach should be combined to yield a suitable educational strategy.