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The conceptual profile of Equilibrium and its contributions to the teaching of Chemical Equilibrium
Abstract
The learning of scientific concepts is one of the main research subjects in science education. Although little used, the theory of conceptual profiles allows the study of this knowledge, taking into account the presence of different ways of thinking about a certain concept in the same individual. This study aimed to build a conceptual profile for the concept of equilibrium and, based on this profile, relate it to the teaching and learning process of chemical equilibrium. Four zones were proposed to comprise the profile, called intuitive, static, kinetic and energetic. Subsequently, we analyzed the responses obtained in a questionnaire by students of Chemistry courses in order to group similar ways of speaking into categories related to the concept of equilibrium and the proposed zones for the conceptual profile. In the answers, we found some alternative conceptions already identified by the literature. Based on the results, the proposed zones for the conceptual profile of equilibrium indicate that establishing associations between the state of chemical equilibrium and the notion of equality can lead to conceptual errors and, therefore, it is suggested to give priority to the notion of stability. We also propose the use of studies on the History and Philosophy of Sciences applied to the teaching of chemical equilibrium to stimulate the emergence, dialogue and enrichment between the zones of conceptual profile in individuals.
... A Figura 1 apresenta o exemplo de um perfil conceitual desenvolvido por Amaral e Mortimer (2001) para o conceito de calor. Outros conceitos e ontoconceitos já foram modelados nessa mesma perspectiva, a exemplo de átomo (Mortimer, 1994), entropia e espontaneidade (Amaral, 2004), vida (Coutinho, 2005), adaptação (Sepulveda, 2010), substância (Silva & Amaral, 2013), energia (Simões--Neto, 2016) e equilíbrio (Silva Costa & Santos, 2022), entre outros. ...
RESUMO: Perfil conceitual é um modelo que caracteriza a heterogeneidade do pensamento conceitual na significação dos conceitos científicos, assumindo a coexistência, nos indivíduos, de dois ou mais modos de significar um mesmo conceito, quando ele é mobilizado em diferentes contextos. Esta pesquisa partiu da seguinte questão: quais diretrizes podem fundamentar o planejamento do ensino de ciências baseado na teoria dos perfis conceituais? Para tanto, lançamos mão de um estudo teórico-bibliográfico a partir do qual analisamos um conjunto de teses e dissertações que desenvolveram intervenções de ensino das ciências amparadas por essa teoria. Essa análise nos permitiu enunciar diretrizes teórico-metodológicas para o planejamento de intervenções de ensino respaldadas pela teoria dos perfis conceituais.
... Figure 1 presents an example of a conceptual profile developed by Amaral and Mortimer (2001) for the concept of heat. Other concepts and ontoconcepts have already been modeled in this same perspective, such as the atom (Mortimer, 1994), entropy and spontaneity (Amaral, 2004), life (Coutinho, 2005), adaptation (Sepulveda, 2010), substance (Silva & Amaral, 2013), energy (Simões-Neto, 2016) equilibruim (Silva Costa & Santos, 2022), among others. (Mortimer & Amaral, 2001) Zones Description ...
Conceptual profile is a model that characterizes the heterogeneity of conceptual thinking in the meaning of scientific concepts, assuming the coexistence, in individuals, of two or more ways of meaning the same concept, when it is mobilized in different contexts. This research started from the following question: which guidelines can support the planning of science teaching based on the theory of conceptual profiles? In order to do so, we used a theoretical-bibliographic study, in which we analyzed a set of theses and dissertations that developed science teaching interventions supported by the theory. This analysis allowed us to enunciate theoretical-methodological guidelines for the planning of teaching supported by the theory of conceptual profiles.
In recent years, the younger generation of the Iranian population has experienced rapid social and cultural changes. One pattern formed because of changing the culture and attitude of the younger generation is white marriage, which is about to become one of the new challenges of Iranian society. The aim of this study was to investigate the socio-cultural factors affecting the change in youth attitudes towards marriage in three cities, including Tehran, Mashhad, and Isfahan. The theoretical framework of this research was interpretative and qualitative methodological framework, along with grounded theory that was used to determine the effective socio-cultural factors on changing young people’s attitude towards marriage. The findings indicated that attitude towards marriage was included of two types as follows: the first type were the people who believed that cultural factors and traditional customs are related to the permanent marriage. The second type was those who were affected by some socio-cultural factors such as lack of belief in permanent marriage, the concept, and were ultimately inspired to unlicensed cohabitation or white marriage. It was found that socio-cultural factors such as age, education, employment, acquaintance, duration of acquaintance, violence against women, and family play an important role in the tendency of white marriage among young people. Lack of acceptance from society and family, lack of support and having a secret relationship are some of the limitations of this way of life. The results of the present study, considering the theoretical and experimental background, showed that social changes, transitional culture, defective modernity and socio-cultural factors are involved in determining the phenomenon of cohabitation. This research is published in 2021 by Mehri publication House with open door “A Comprehensive Research Study on White Marriage (Cohabitation) in Iran ”
Key words: Marriage, socio-cultural, white marriage, young people, Iran
To read a related articles and to download click here: https://kameelahmady.com/white-marriage/
Child labour has been a cause of concern in many social, political and administrative circles for several decades; nonetheless, child labour research, regulations and initiatives have mostly concentrated on boys, presuming that the needs and requirements of girls are the same as those of boys. As a result, working girls often became ‘invisible’, yet they make up a very large proportion of working children. A global study project conducted in 2002 shows no substantial difference between girls and boys in economic engagement, but, in many societies, girls and boys are perceived differently. Typically, girls are perceived to have a lower value; hence they are considered to be inferior to their male counterparts. Both girls and boys are vulnerable to child-labour exploitation, albeit in different ways. Boys and girls have different coping strategies and deal with different problems of child labour in various ways (Kolomiyets & Murray, 2004).
It should be noted that the prenatal and early childhood environments, as well as states of children’s health, are significant predictors of their intellectual development, educational achievements and future health. Child labour, in its different forms, compromises a child’s physical and mental health, as well as their education, growth and development (International Labour Organization, 2004). These effects of child labour, in turn, have a significant impact on the health and success of parents, particularly mothers, and threaten the potential of upcoming generations. Although girls are exposed to far more types of work than boys, due to societal attitudes toward the different roles of boys and girls, girls frequently face greater hardship and are more likely to be exploited. There are some gender differences in child labour, which necessitates further investigation. Society prescribes the types of tasks that are usually performed by girls and boys, and gender is a key factor in work organisation. Gender roles as key cultural determinants, along with family status and tradition, play important roles in the types of work activities that boys and girls undertake.
Therefore, the purpose of this study is to highlight the gender aspects of child labour by systematically reviewing studies in the field of child labour and seeking answers to the question ‘What are the gender differences in child labour in terms of its amounts, causes, forms, natures and performances?’
Keywords: Worst forms of child labour, gender, children, grounded theory
One pattern that has emerged today because of changing attitudes of young people in today's society is white marriage, which has become one of the social challenges. White marriage is the way of life without registering a formal and legal marriage that is accepted differently among young people. The purpose of this study is to study the status of white marriage among young people who have experienced this lifestyle, the causes of the tendency to this lifestyle and its consequences, in three metropolises, including Tehran, Mashhad, and Isfahan. The theoretical framework of this research was interpretative and qualitative methodological framework, along with a grounded theory that was used to determine the effective on changing young people’s attitude towards marriage, including law, religious and custom. Some environmental factors such as religiosity, tendency of individuals to official marriage and its reasons, incidence of pregnancy and abortion, and Importance of virginity were studied. The existence of laws, traditions and religious beliefs related to these factors in Iranian families has led to a change in young people's attitudes towards formal marriage and their greater desire to continue the relationship and choose white marriage. The results of the research indicated that the social rules, religious and custom, which are governing, are involved in determining the phenomenon of cohabitation. Lack of acceptance by society and family, lack of legal protection and having a secret relationship are some of the limitations of this way of life. This research is published in 2021 by Mehri publication House with open door “A Comprehensive Research Study on White Marriage (Cohabitation) in Iran” .
Keywords: Marriage, cohabitation, youth, attitude, Law, religion, custom, Iran
To read related articleس and to download click here: https://kameelahmady.com/white-marriage/
Se analizan cuatro problemas de selectividad de equilibrio químico. Este análisis concluye que la resolución de problemas de este tema se basa en una metodología de enseñanza que propicia un aprendizaje memorístico, no signifi cativo. Los profesores pueden estar transmitiendo, e incluso reforzando, algunos de los errores detectados. Las reglas de Le Chatelier se utilizaron de forma casi exclusiva a la hora de predecir los desplazamientos de los equilibrios químicos. Cambios de concentración causados por variación del volumen se asociaron principalmente con las variaciones de masa resultantes del correspondiente desplazamiento. Errores de comprensión del comportamiento de los gases fueron obstáculos a la hora de predecir cambios de presión parcial. Finalmente, el principio de Le Chatelier se utiliza de forma muy extendida más allá de su rango de aplicabilidad.
Propõe-se uma estratégia metodológica de transformar os resultados das pesquisas em perfis conceituais em informações significativas e heurísticas para planejamento de ensino na educação básica, por meio da pesquisa em design educacional (design research). Aplicando a referida metodologia aos resultados de estudos com um perfil de adaptação, são apresentadas rotas de aprendizagem, objetivos, conteúdos, contextos para ensino médio de evolução, e diretrizes para uso da linguagem e gestão do discurso em sala de aula. Como resultado, essas informações são sistematizadas e enunciadas na forma de princípios de design de intervenções para o ensino médio de evolução.
As salas de aula de ciências são espaços formais e privilegiados, ideais para difundir o conhecimento científico, problematizar situações e promover uma aprendizagem significativa. O ensino por investigação auxilia na mudança e/ou construção do perfil conceitual do aluno, e suas metodologias permitem que o mesmo seja protagonista do seu aprendizado. Este trabalho versa sobre a experiência exitosa e os resultados obtidos ao utilizar-se o recurso ‘quadrinhos’ como forma de sistematizar conceitos aprendidos, em Química, com alunos do segundo ano do ensino médio em uma escola estadual do médio-Piracicaba. Foi aplicada uma sequência didática de caráter investigativo, para introduzir o conteúdo de acidez e basicidade de soluções, dividida em quatro aulas. Os resultados obtidos foram satisfatórios considerando-se que os alunos não tiveram contato prévio com o conteúdo. A sequência investigativa colaborou para a construção sólida de conceitos relacionados ao tema abordado. Com base nos resultados, ficou claro que o uso de quadrinhos contribuiu para a sistematização de conceitos, estimulando a vontade de pesquisar atrelada ao despertar do saber científico, bem como o trabalho em equipe.
In this paper it is performed a historical account of the theoretical roots that grounded the following four key basic ideas of chemical equilibrium: ‘incomplete reaction’, ‘reversibility’, ‘equilibrium constant’ and ‘molecular dynamics’. These notions developed in nineteenth-century as a consequence of the evolution of the concept of chemical affinity. The discussion begins with the presentation of the earliest affinity table [‘Table des rapports’] published in 1718 by Geoffroy. Afterwards, it is examined Bergman’s compilation. The theory supporting this arrangement assumed that chemical displacement reactions were complete and could not be reversed. It is analysed how Berthollet’s model showed the inadequacy of this view. His new conceptual considerations established that the amount of the substances involved in a reaction was an essential factor determining its direction, which accounted for the early concepts of incomplete reaction and reversibility. Guldberg and Waage specified the role of mass in chemical equilibrium reactions as they considered the concentrations of the chemicals involved, formulating the first chemical equilibrium mathematical equation that approximates what is called nowadays chemical equilibrium constant. Finally, it is presented how Pfaundler was the first to consider the kinetic theory in the interpretation of the macroscopic properties of equilibrium reactions.
Esta pesquisa objetivou analisar estratégias didáticas utilizadas por dois professores de química e aspectos da dinâmica discursiva estabelecida durante aulas sobre o conceito de equilíbrio químico. A investigação ocorreu no segundo semestre de 2014 em duas escolas, uma pública e outra privada, de Recife (PE), em turmas do 2º ano do ensino médio. Foi feita uma investigação de natureza etnográfica, a partir da observação direta e sistemática da sala de aula, sendo 5 aulas gravadas em vídeo. Na análise da dinâmica discursiva, foram identificados abordagens comunicativas e padrões de interação estabelecidos pelos professores em sala de aula. Os resultados mostraram que exposição oral do conteúdo foi a estratégia didática predominantemente adotada pelos dois professores, que estabeleceram uma abordagem comunicativa interativa/de autoridade. Questionamentos e resolução de exercícios foram realizados durante as aulas, e possibilitaram interações entre professores e estudantes, mas isso não foi suficiente para desencadear um processo dialógico de construção de significados para o conceito de equilíbrio químico. Em geral, os padrões de interação estabelecidos nas aulas se limitaram às tríades I-R-A (Iniciação–Resposta–Avaliação), com a identificação de poucas cadeias interativas, sendo mais usada pelos professores a iniciação de escolha, na qual os estudantes ficam limitados a optar por respostas já definidas, não expressando suas próprias ideias. Finalmente, verificamos que estratégias didáticas propostas por diferentes pesquisas encontradas na literatura para a abordagem de equilíbrio químico não parecem ter tido impacto na prática dos professores investigados.
Resumen: Este trabajo realiza una reconstrucción histórica de los orígenes de la ley de equilibrio químico. Tras una breve presentación de la evolución de ideas que permitió formular la primera ecuación matemática de lo que hoy se conoce como constante de equilibrio, se analizan los principios teóricos que inicialmente fundamentaron el estudio cuantitativo del equilibrio químico. Se discute cómo el empleo del len-guaje matemático ayudó a construir el nuevo conocimiento químico. Finalmente, se estudian las primeras interpretaciones que intentaban comprender cómo se alcanzaba la situación de equilibrio químico. Palabras clave: Reacción química, equilibrio químico, constante de equilibrio, cinética química, lenguaje matemático. Abstract: This work performs a historical reconstruction on the fundamentals of the equilibrium law. After a brief presentation of the evolving ideas that made possible the first mathematical equation of what we know nowadays as the equilibrium constant, the theoretical principles that initially grounded the quantitative study of chemical equilibrium are analysed. It is discussed how the use of mathematical language helped in the construction of the new chemical knowledge. The first interpretations accounting for how the equilibrium situation was eventually achieved are also studied. Est e trabajo presenta la evolución en la idea de reacción química que desembocó en el concepto de equilibrio quí-mico. En concreto, trata de conocer el origen de la prime-ra formulación de la ley de equilibrio químico, realizando un seguimiento de la transición de las distintas nociones que permitieron su fundamentación inicial, así como la presentación, en paralelo, de los principales actores que participaron en este proceso. El punto de partida de este estudio histórico es el sig-nificado que se otorgó a las tablas de afinidad química, que tuvieron su punto álgido de desarrollo en los últimos veinticinco años del siglo xviii y en los primeros años del siglo xix. De esta primera idea de que las reacciones quí-micas se producían siempre de forma completa y en un solo sentido, se empezó a poner claramente de manifies-to, a partir de principios del siglo xix, que el sentido de una reacción química se podía invertir, indicando además que estos procesos nunca se producían de forma completa. Inicialmente, estas propiedades de las reacciones químicas se conceptualizaron asumiendo un estado de equilibrio estático. La interpretación dinámica de los procesos de equilibrio químico se produjo en los primeros años de la segunda mitad del siglo xix. Los primeros trabajos en los que se emplearon ecua-ciones matemáticas en el estudio de procesos de equilibrio químico también corresponden a investigaciones publica-das en el inicio de la segunda mitad del siglo xix. En estos estudios se encuentra por vez primera la ecuación de lo que hoy denominamos constante de equilibrio. Este análi-sis se centra en los siguientes aspectos: a) cómo se llegó a la primera deducción experimental de esta constante; b) sus distintas formulaciones, realizadas desde enfoques diferen-tes; c) los intentos iniciales de su justificación teórica, fina-lizando esta reconstrucción histórica con la exposición del primer estudio verdaderamente cinético, producido hacia finales del siglo xix. reacciones completas y en un sólo sentido: las tablas de afinidad química El período de tiempo comprendido entre el último cuar-to del siglo xviii y el primer cuarto del siglo xix supuso el mayor desarrollo de las denominadas tablas de afinidad química. Estas ordenaciones de reactividad relativa se ba-saron en la primera tabla elaborada por científico francés E. F. Geoffroy [1] en 1718 (Fig. 1), en la que se sintetizaba,
This paper outlines the historical evolution of the concept of chemical affinity that eventually supported the concept of chemical equilibrium. It provides the theoretical roots that grounded the following four key basic ideas of chemical equilibrium: ‘reversibility’, ‘incomplete reaction’, ‘equilibrium constant’ and ‘dynamic equilibrium’. The starting point of this historical reconstruction is the state of the art in the elaboration of the first affinity tables, based on the concept of elective affinities, during the eighteenth century. It is discussed how Berthollet reworked this idea, considering that the amount of the substances involved in a reaction was an essential factor determining its direction, which accounted for the early concepts of incomplete reaction and reversibility. Guldberg and Waage considered the concentrations of the chemicals involved, instead of their mass and formulated the first mathematical equations accounting for chemical equilibrium reactions. Afterwards, it is presented how Pfaundler provided the seminal ideas concerning a dynamical molecular interpretation of the macroscopic properties of equilibrium reactions. This material is intended to serve as a supplementary reading for an introductory course in physical chemistry.
Dentro do paradigma funcionalista, caracterizado pelo objetivismo filosófico e pela sociologia da manutenção do status quo, a teoria institucional e da ecologia das organizações são amplamente estudadas para explicar por que as organizações podem ser, paradoxalmente, tão diferentes e tão semelhantes. A teoria da ecologia das organizações defende que existe grande diferença entre as organizações e, com o passar do tempo, aquelas mais adaptadas são selecionadas pelo ambiente. Isso faz com que as empresas se mantenham mais semelhantes, seja, simplesmente, pela própria seleção, seja pela busca da uniformidade àquelas que são bem sucedidas. Essa é a ideia central da teoria institucional, em que a existência dos isomorfismos coercitivo, mimético e normativo padroniza as organizações. Ocorrendo uma mudança importante no ambiente, o ciclo reinicia, havendo uma nova seleção e a consequente busca do isomorfismo. Finalmente, pode-se observar que uma teoria complementa a outra, gerando um ciclo para a existência das organizações, que não podem ser vistas como excludentes.
In this paper, we briefly address the theoretical and methodological grounds of the conceptual profile theory and discuss two empirical studies aiming at constructing conceptual profile models and using them to analyze classroom discourse in different sciences, chemistry (entropy and spontaneity) and biology (adaptation). The basic idea is to illustrate how these models were built, considering differences and similarities between the methods used for this purpose. Conceptual profiles are models of different modes of seeing and conceptualizing the world used by individuals to signify their experience. They are built for a given concept and are constituted by several zones, each representing a particular mode of thinking about that concept, related to a particular way of speaking. Each zone is individuated by ontological, epistemological, and axiological commitments underlying discourse. We will show how different concepts, situated in sciences with different levels of conceptual polysemy, demand different methodologies to deal with the variation found in meaning making in the sociocultural, ontogenetic, and microgenetic domains.
Resumo Este artigo trata da construção de um perfil conceitual de 'vida'. Partimos da hipótese de que o conceito de vida é polissêmico, admitindo vários significados possíveis e devendo comportar, portanto, um perfil conceitual. Buscamos demarcar zonas que poderiam constituir esse perfil conceitual. Realizou-se a investigação com alunos da graduação em ciências biológicas (ICB/UFMG). Considerando aspectos epistemológicos e ontológicos, identificamos três zonas que representam três níveis de compreensão do conceito de vida. Essas três zonas foram designadas "internalismo", incluindo concepções nas quais vida é entendida como processos ou propriedades inerentes ao vivente; "externalismo", que representa uma compreensão da vida como algo externo e separado do vivente, podendo ser vista como algo que vem de fora ou que tende a uma finalidade para além do ser vivo; e "relacional", na qual a vida é concebida como uma relação de entidades e/ou sistemas, sendo a definição dada em termos de relações. Abstract This paper reports the building of a conceptual profile of 'life'. We departed from the hypothesis that the concept of life is polysemous, showing several possible meanings, and, thus, admitting a conceptual profile. We strived, then, for demarcating the zones that could constitute this conceptual profile. The research was conducted with Biology majors from the Universidade Federal de Minas Gerais. Taking into account epistemological and ontological aspects, we identified three zones representing three levels of understanding of the life concept. We named these zones "internalism", in which life is understood as inherent processes or properties of living beings; "externalism", representing an understanding of life as something external to and apart from living beings, as something which comes from outside or tends to a goal which is beyond the living being; and "relational", in which life is conceived as a relation between entities and/or systems, and the definition is given in terms of relations.
Neste artigo, tivemos como objetivo propor um perfil conceitual para o conceito de substância. O perfil foi proposto a partir de um levantamento de dados em diversas fontes como: textos de História da Química, artigos na literatura em Ensino de Ciências, questionários e entrevistas semiestruturadas, aplicados a estudantes do ensino médio e superior. Essas fontes possibilitaram a constituição de um conjunto de dados representativos de três domínios genéticos: ontogenético, sociocultural e microgenético. Dados obtidos na pesquisa bibliográfica articulados àqueles da pesquisa empírica foram agrupados em categorias, que posteriormente constituíram zonas para o perfil conceitual de substância. Cada zona do perfil foi caracterizada por compromissos epistemológicos e ontológicos distintos e as seguintes zonas foram propostas: generalista, essencialista, substancialista, racionalista e relacional.
Abstract In this paper we aimed to propose a conceptual profile to the concept of substance. The profile was proposed considering data collected from sources such as: History of Chemistry, literature in Science Education, questionnaires and interviews.
With this paper, our main aim is to contribute to the realisation of the chemical reactivity concept, tracing the historical evolution of the concept of chemical affinity that eventually supported the concept of chemical equilibrium. We will concentrate on searching for the theoretical grounds of three key chemical equilibrium ideas: 'incomplete reaction', 'reversibility' and 'dynamics'. In addition, the paper aims to promote teachers' philosophical/historical chemical knowledge. The starting point of this historical reconstruction will be the state of the art in the construction of the first affinity tables, based on the concept of elective affinities, during the 18th century. Berthollet reworked this idea, considering that the amount of the substances involved in a reaction was a key factor accounting for the chemical forces. Guldberg and Waage attempted to measure those forces, formulating the first affinity mathematical equations. Afterwards, the first ideas providing a molecular interpretation of the macroscopic properties of equilibrium reactions are presented. Eventually, theoretical chemists integrated previous findings into a new field: thermodynamics. This historical approach may serve as a base for an appropriate sequencing of the teaching and learning of chemical equilibrium. Hence, this paper tries to go beyond the simple development of teachers' conceptions of the nature of chemistry, for it gives suggestions about how teachers may translate such understandings into classroom practice.
This paper discusses three key issues relevant to secondary school
chemistry teaching. They arise from a study of students' understanding
of chemical equilibrium using qualitative and quantitative research
methods. These issues were (i) the relative usefulness of different
levels of explanation that are used by teachers and students to make
predictions about the effect of changes to equilibrium mixtures, (ii)
the interpretation of commonly used terms in the topic of chemical
equilibrium, and (iii) the specific nature of the content of equilibrium
and the problems associated with simplifying this content for students.
Chemistry is regarded as a difficult subject for students. The difficulties may lie in human learning as well as in the intrinsic nature of the subject. Concepts form from our senses by noticing common factors and regularities and by establishing examples and non-examples. This direct concept formation is possible in recognising, for instance, metals or flammable substances, but quite impossible for concepts like ‘element’ or ‘compound’, bonding types, internal crystal structures and family groupings such as alcohols, ketones or carbohydrates. The psychology for the formation of most of chemical concepts is quite different from that of the ‘normal’ world. We have the added complication of operating on and interrelating three levels of thought: the macro and tangible, the sub micro atomic and molecular, and the representational use of symbols and mathematics. It is psychological folly to introduce learners to ideas at all three levels simultaneously. Herein lies the origins of many misconceptions. The trained chemist can keep these three in balance, but not the learner. This paper explores the possibilities, for the curriculum, of a psychological approach in terms of curricular order, the gradual development of concepts, the function of laboratory work and the place of quantitative ideas. Chemical education research has advanced enough to offer pointers to the teacher, the administrator and the publisher of how our subject may be more effectively shared with our students. [Chem. Educ. Res. Pract. Eur.: 2000, 1, 9- 15]
Those propositions deemed necessary for an understanding of chemical equilibrium and Le Chatelier's Principle were defined by the investigators and validated.Thirty, Year 12 Western Australian chemistry students (17 years of age) who had studied chemical equilibrium were interviewed and students’ responses were coded into various categories of misconception that had been identified. The most significant misconceptions revealed by the study were: 1. The rate of the forward reaction increases with time from the mixing of the reactants until equilibrium is established;2. a simple arithmetic relationship exists between the concentrations of reactants and products at equilibrium; and3. when a system is at equilibrium and a change is made in the conditions, the rate of the favoured reaction increases but the rate of the other reaction decreases.4. Students’ prior experience of reactions that proceed to completion appears to have influenced their conception of equilibrium reactions; many students failed to discriminate clearly between the characteristics of completion reactions and reversible reactions.
A survey of students' alternative conceptions regarding chemical equilibrium. Classification and synthesis of suggestions for teaching) The authors presents an exhaustive survey of empirical research published in books and journals concerning stu- dents' alternative conceptions of ''chemical equilibrium'' and seeks to systematize and categorize the difficulties and alter- native conceptions discovered. Also included for each of these categories are the teaching suggestions proposed by the authors surveyed for instruction in this central topic in chemistry. The information collected is considered to be of particular utility to secondary and undergraduate teachers who seek to incorporate innovative teaching methods in their courses.
We discuss two questions that deal with changes in concentration or partial pressures of the gases involved in chemical equilibrium systems. This paper analyses the responses and reasons given by both high school and fourth-year university students as well as by both pre-service and inservice teachers. The sample was taken from the Spanish context, where Le Chatelier’s principle is compulsory for Grade-12 chemistry students as well as for first year university students. It is reported that Le Chatelier’s qualitative statements were the main and almost exclusively conceptual tools used to predict equilibrium shifts when changing pressure, volume or mass. In some cases, incorrect rules led students to state correct shift predictions. Changes in concentration caused by a variation in the volume of the equilibrium vessel were mainly associated with equilibrium shift mass changes. Equilibrium law was not used at all by students; a minor number of teachers did mention the equilibrium constant in their explanations. Thus, few correct answers were ascertained. Gas behaviour misunderstandings were one of the most important obstacles when coping with changes in partial pressure due to changes in both mass and volume. Many responses concentrated on physical behaviour of gases, instead of going beyond using the equilibrium law. Many teachers erroneously associated changes in partial pressure caused by a variation in the volume of the equilibrium vessel with equilibrium shift mass changes. Eventually, this paper presents evidence, both theoretical and empirical, to conclude that Le Chatelier’s rules should be abandoned completely in chemical education. Thus, it suggests the teaching of these problems on the basis of the equilibrium law, and the focussing on the ‘history’ of the system under consideration. Obviously, such an approach will not solve all the problems one has with Le Chatelier’s rules, but it is a promising approach. [Chem. Educ. Res. Pract., 2004, 5, 281-300]
Neste artigo, discutimos
bases teóricas e epistemológicas da abordagem dos
perfis conceituais, concebida como uma maneira de
modelar a heterogeneidade do pensamento e da linguagem
em salas de aula de ciências. Nós distinguimos
entre duas visões sobre conceitos: (1) conceitos como
modelos ou esquemas mentais de objetos ou eventos;
(2) conceitos como exibindo significados relativamente
estáveis e existindo apenas nas linguagens naturais e
nos sistemas de conhecimento, e diferenciando-se da
conceitualização, um processo dinâmico que ocorre nas
mentes dos indivíduos, como resultado de interações
socialmente situadas com eventos e experiências externas.
Nós discutimos a aprendizagem da perspectiva da
abordagem dos perfis conceituais, tratando-se como
envolvendo os processos relacionados de enriquecimento
de perfis conceituais e tomada de consciência
tanto da heterogeneidade quanto da demarcação de
modos de pensar e falar. Por fim, discutimos se a abordagem
dos perfis conceituais é relativista, defendendo
que ela é, antes, uma abordagem pragmatista objetiva.
Resumo: A investigação teve como propósito investigar e analisar os conhecimentos de futuros professores de Química sobre Equilíbrio Químico, identificando suas dificuldades e condicionantes, em uma universidade pública do estado de Minas Gerais. Foram investigados 47 licenciandos matriculados em disciplinas sobre ensino de Química. Em consonância com outros estudos foi possível perceber que os resultados são similares a outros encontrados para alunos do ensino médio. Desse modo, é possível inferir que os futuros professores possuem conhecimentos que se aproximam dos estudantes do ensino médio. Entre eles podemos citar os que se relacionam com a imagem do sistema em equilíbrio (recipiente fechado, dinamismo, constância das concentrações, composição da mistura em equilíbrio) e com os aspectos cinéticos (modo de colisões, constância e variação de velocidades de reação em diferentes momentos). Desse modo, as análises apresentadas mostram que é necessária a realização de investimentos na formação científica dos futuros professores, tendo em vista que os problemas conceituais dos mesmos podem passar a existir refletido nos conhecimentos apresentados pelos estudantes. Desse modo, se não investirmos na formação docente as dificuldades conceituais relacionadas a equilíbrio químico serão mantidas nos diferentes níveis de ensino. Abstract: The inquiry aimed to investigate and to analyze the knowledge of future professors of Chemistry on Chemical Equilibrium, identifying their difficulties, in a public university of the state of Minas Gerais. 47 registered students on the Chemistry discipline had been investigated. According to other studies it was possible to notice that the results are similar to other ones found for high school students. Therefore, it is possible to deduce that the future professors have the knowledge that approaches to the high school students. Between them we can cite the ones that are related to the image of the system in balance (receiving closed, dynamism, concentrations constancy, mixture composition in balance) and with the kinetic aspects (collisions ways, constancy and variation of reaction speeds at different moments). In conclusion, the analyses presented show that it is necessary to invest in the scientific formation of the future professors, seeing that the
span>En química, así como en todas las ciencias y en la vida diaria, se emplean analogías, metáforas o modelos para ayudar a explicar un fenómeno que no es observable. Sin embargo, nos dicen Treagust, Duit y Nieswandt (2000) que la literatura sobre la utilización de analogías en la enseñanza y el aprendizaje de la ciencia es ambivalente acerca de la validez o invalidez de la presentación de analogías sencillas o múltiples como la mejor manera de enseñar (Goswami, 1993; Zook, 1991).</span
The language of science has many words and phrases whose meaning either changes in differing contexts or alters to reflect developments in a given discipline. This book presents the authors’ theories on using ‘conceptual profiles’ to make the teaching of context-dependent meanings more effective. Developed over two decades, their theory begins with a recognition of the coexistence in the students’ discourse of those alternative meanings, even in the case of scientific concepts such as molecule, where the dissonance between the classical and modern views of the same phenomenon is an accepted norm.
What began as an alternative model of conceptual change has evolved to incorporate a sociocultural approach, by drawing on ideas such as situated cognition and Vygotsky’s influential concept of culturally located learning. Also informed by pragmatist philosophy, the approach has grown into a well-rounded theory of teaching and learning scientific concepts. The authors have taken the opportunity in this book to develop their ideas further, anticipate and respond to criticisms—that of relativism, for example—and explain how their theory can be applied to analyze the teaching of core concepts in science such as heat and temperature, life and biological adaptation. They also report on the implementation of a research program that correlates the responsiveness of their methodology to all the main developments in the field of science education. This additional material will inform academic discussion, review, and further enhancement of their theory and research model.
A proposta deste trabalho foi mostrar que a contextualização constitui uma ferramenta metodológica importante para o desenvolvimento de conceitos no processo de ensino e pode ser bem aplicada ao tema Equilíbrio Químico, a partir de reações que façam parte do cotidiano dos alunos. Foi realizado um estudo de caráter descritivo, exploratório com abordagem qualitativa. Com o uso de exemplos do cotidiano durante a prática docente, pode-se perceber a importância da contextualização no ensino de química, pois a aula contextualizada tornou-se uma estratégia que contribuiu para a motivação e interesse dos alunos pela disciplina. Os resultados evidenciam que quando um determinado assunto é desenvolvido utilizando-se da contextualização e da interdisciplinaridade além de um maior interesse há um melhor desenvolvimento por parte dos alunos. Portanto a aula contextualizada se apresenta com uma estratégia essencial para o processo ensino/aprendizagem, pois como é amplamente conhecido no processo da educação em ciências, as tradicionais estratégias de ensino, como o quadro e pincel, não são suficientes para assegurar que os alunos realmente assimilem os conceitos científicos. Assim, pode-se concluir que a contextualização é uma ferramenta que contribui significativamente para o processo de ensino/aprendizagem.
This chapter deals with one of the most important concepts that help establishing the onto concept of matter: the concept of molecule. To understand modern chemistry, we cannot resort only to the classical molecules or to its modern counterparts: dynamic, polynuclear, or supramolecular frameworks. All of them are complementary views of the chemical world. They are not applicable to the same problems, but we cannot resort to only one of them to explain all the chemical phenomena. If we look out of chemistry, into everyday culture, this scientific complementarity should be expanded to incorporate other meanings in a complete conceptual profile of molecule. In this chapter we are going to report how the concept of molecule evolved in the sociocultural domain, trying to identify its genetic roots. We are also interested in examining the contexts of application of each conceptual zone, trying to establish epistemological and ontological consequences of each zone for the development of chemistry. Related to the zones that are outside the scientific domain, we are interested in showing contemporary uses of ideas that bear strong similarity with these zones. Finally we discuss some implications of determining this conceptual profile of molecule for chemistry teaching.
In this chapter we present the different methodological options that can inform the research on conceptual profiles. These options include studies aiming at identifying possible zones to build a conceptual profile model, investigations conducted in order to understand how the different zones of a conceptual profile model evolve in a specific population, or researches about how different zones of a profile emerge in discursive interactions in the classroom. The main methodological principle that guides researches carried out to identify possible zones in order to build a specific conceptual profile model resides in the Vygotskyan maxim that it is only possible to have a full picture of the genesis of a concept if we study it in different genetic domains. In the case of investigations about how the distribution of profile zones evolves in a specific population, we use questionnaires with a range of questions that makes it possible to produce different contexts, favoring the appearance of different zones. Finally, to discuss how different zones of a profile emerge in discursive interactions in the classroom, we model the discursive dynamics and meaning making in teaching episodes through the integrated application of a conceptual profile of a given concept and the analytical framework developed by Mortimer and Scott.
In this chapter, we discuss the charge that the conceptual profile theory would be relativist. After contrasting rationalism and relativism, we elaborate the epistemological grounds of the theory in terms of an objective pragmatism, drawing on Peirce’s and Dewey’s philosophies, and discuss the differences between this philosophical position and relativist views. For a pragmatist, there is no problem in comparing different ways of thinking, provided that this comparison is not made in abstract, but always with a clear connection to concrete situations in which we should make decisions and act. From this we derive one of the learning goals in the profile theory: to become aware of the several modes of thinking available in a sociocultural circumstance and of the domains in which their application shows pragmatic value.
In this chapter, we address the heterogeneity in thinking and talking in science classrooms from the perspective of the conceptual profile approach. In order to model the different ways of conceptualizing objects and events that a person can employ, we introduce the conceptual profile approach and discuss learning from that perspective, as the related processes of enriching an individual’s conceptual profile and becoming aware of the heterogeneity of thought and language, and the contexts in which distinct modes of thinking can be applied. We also consider how the conceptual profile approach fits into an analysis of classroom discourse, by arguing that it provides a heuristically powerful tool to analyze the cognitive dimension of discourse. We also offer an example of classroom discourse analysis in order to illustrate the use of conceptual profiles.
Conceptual profiles are models of the heterogeneity of thought and language in the classroom, embedded into a theoretical structure that addresses school science social language learning from a sociocultural perspective. They are related to an understanding of concepts that denies its interpretation as entirely internal mental structures and conceives concepts as parts of natural languages or knowledge structures, entities or linguistic structures external to the mind that do not become entirely internalized. Conceptual thinking is conceived as an emergent process, always produced through interaction between individuals and external experiences. Since the theory takes as a basis Vygotsky’s general genetic law of cultural development, according to which individual thinking develops through the internalization of cultural tools available in social interactions, when we deny that there can be concept internalization, a potential contradiction appears, which is discussed and solved in this paper based on Vygotsky’s theory and on situated cognition. We also elaborate on the characteristics of conceptual profiles as models of the different ways of seeing and conceptualizing the world present in a given sociocultural circumstance, discuss the nature of learning according to the conceptual profile theory, and examine an example of such model, built to deal with the semantic dimension of teaching and learning about heat and temperature.
Research in science education has revealed that many students struggle to understand chemical reactions. Improving teaching and learning about chemical processes demands that we develop a clearer understanding of student reasoning in this area and of how this reasoning evolves with training in the domain. Thus, we have carried out a qualitative study to explore students reasoning about chemical causality and mechanism. Study participants included individuals at different educational levels, from college to graduate school. We identified diverse conceptual modes expressed by students when engaged in the analysis of different types of reactions. Main findings indicate that student reasoning about chemical reactions is influenced by the nature of the process. More advanced students tended to express conceptual modes that were more normative and had more explanatory power, but major conceptual difficulties persisted in their reasoning. The results of our study are relevant to educators interested in conceptual development, learning progressions, and assessment.
This book in the highly respected Cambridge History of Science series is devoted to the history of the life and earth sciences since 1800. It provides comprehensive and authoritative surveys of historical thinking on major developments in these areas of science, on the social and cultural milieus in which the knowledge was generated, and on the wider impact of the major theoretical and practical innovations. The articles were written by acknowledged experts who provide concise accounts of the latest historical thinking coupled with guides to the most important recent literature. In addition to histories of traditional sciences, the book covers the emergence of newer disciplines such as genetics, biochemistry, and geophysics. The interaction of scientific techniques with their practical applications in areas such as medicine is a major focus of the book, as is its coverage of controversial areas such as science and religion and environmentalism
The readership for this book includes professionals in psychology, developmental psychology, cultural historical psychology, education and linguistics. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
The purpose of this study was to describe the evolution of conceptions about chemical equilibrium based on observations/interactions with selected chemistry students using an instructional design which included constructivist strategies such as POEs, analogies, small group discussions, and journal writing. Two intact classes with a total of 75 students enrolled in a general chemistry course participated in the study. The conceptual evolution of six students was followed through the use of pre-tests, transcripts of audiotaped and videotaped group discussions, written answers to activity sheets, learning journals, interviews, and post-tests. The students started with concepts of complete reactions and progressed to developing concepts of reversibility but had difficulty with the dynamic nature of reversible reactions. The use of an analogy using double-sided disks helped in the students' visualization of the microscopic processes taking place and in the properties of systems as they approach and when they reach equilibrium. However, students' conceptions of complete reactions still competed with their conceptions of reversible reactions.
In this paper I draw an overview of a new model to analyse conceptual evolution in the classroom, based on the notion of Conceptual Profile. This model differs from conceptual change models in suggesting that it is possible to use different ways of thinking in different domains and that a new concept does not necessarily replace previous and alternative ideas. According to this model, learning science is to change a conceptual profile and become conscious of the different zones of the profile, which includes commonsense and scientific ideas.
To exemplify how the Conceptual Profile notion can help to understand the evolution of conceptions in the classroom I shall determine the different zones that constitute the epistemological and ontological profile of the concepts of the atom and of physical states of matter.
More attention to the History of Science is needed, as much by scientists as by historians, and especially by biologists, and this should mean a deliberate attempt to understand the thoughts of the great masters of the past, to see in what circumstances or intellectual milieu their ideas were formed, where they took the wrong turning or stopped short on the right track. Fisher 1959, pp. 16-17. On closer examination, however, the hope of finding a "first" comes to grief because of the historically dynamic character of ideas. If we describe a result with sufficient vagueness, there seems to be an endless sequence of those who had something within the vague specifications. Even plagiarists usually introduce innovations! If we specify the idea or result precisely, it turns out that exact duplications seldom occur, So that every mathematical event is a "first", and the priority question becomes trivial.
A comprehensive account of knowledge of the natural world in Europe, ca. 1500–1700. Often referred to as the Scientific Revolution, this period saw major transformations in fields as diverse as anatomy and astronomy, natural history and mathematics. Articles by leading specialists describe in clear, accessible prose supplemented by extensive bibliographies, how new ideas, discoveries, and institutions shaped the ways in which nature came to be studied, understood, and used.
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