Evaluación de berberecho

Department of Chemistry, Universidad de Oriente Apartado Postal 90, Cumaná, Estado Sucre, Venezuela 6101A

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Recent research in science education has recognized the importance of understanding science within a framework that emphasizes the dynamics of scientific research that involves controversies, conflicts and rivalries among scientists. This framework has facilitated a fair degree of consensus in the research community with respect to the following essential aspects of nature of science: scientific theories are tentative, observations are theory-ladden, objectivity in science originates from a social process of competitive validation through peer review, science is not characterized by its objectivity but rather its progressive character (explanatory power), there is no universal step-by-step scientific method. This study reviews research based on classroom strategies that can facilitate high school and university chemistry teachers’ understanding of nature of science. All teachers participated in two Master’s level degree courses based on 34 readings related to history, philosophy and epistemology of science (with special reference to controversial episodes) and required 118 hours of course work (formal presentations, question-answer sessions, written exams and critical essays). Based on the results obtained this study facilitated the following progressive transitions in teachers’ understanding of nature of science: a) Problematic nature of the scientific method, objectivity and the empirical nature of science; b) Kuhn’s ‘normal science’ manifests itself in the science curriculum through the scientific method and wields considerable influence; c) Progress in science does not appeal to objectivity in an absolute sense, as creativity, presuppositions and speculations also play a crucial role; d) In order to facilitate an understanding of nature of science we need to change not only the curricula and textbooks but also emphasize the epistemological formation of teachers.

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Keywords: Science teachers, Nature of science, History, philosophy and epistemology of

science

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Research in science education shows that in most parts of the world, both high school and freshman students are not sufficiently motivated to pursue careers in science. Different research perspectives have attributed this state of affairs to various factors. The perspective based on history and philosophy of science has attributed this to the particular methodology employed by science teachers, textbooks and curriculum developers (Clough, 2006; Jenkins, 2007; Niaz, 2008a; Osborne, 2007; Stinner, 1992). For example, although the idea of testing and hypothesizing is most germane to the physical sciences, its presentation in the classroom is devoid of one of the most important aspects of progress in science, viz., rivalry between conflicting hypotheses. Despite all the reform efforts, classroom environment in most parts of the world is still characterized by a ‘rhetoric of conclusions’ (Schwab, 1974), in which students are told that they must learn this as a famous scientist said so. Ironically, the famous scientist generally had to struggle and argue with his contemporaries in order to present a particular theory, which contrary to popular belief is bound to be superseded, that is the tentative nature of science. It is precisely for such reasons that research in science education has recognized the importance of understanding science within a framework that emphasizes the dynamics of scientific research that involves controversies, conflicts and rivalries among scientists. It is plausible to suggest that such discussions based on ‘science-in-the-making’ and vicissitudes of the scientists can stimulate students’ interest in learning science. Both students and teachers would be more motivated if they knew that are present day theories will change and that they could play an important role in this endeavor. In contrast, our present textbooks, teachers and curricula provide a vision of science which is static and immune to change. Furthermore, teacher education research is difficult and constitutes a relatively new field:

At the same time, teacher education is a relatively new field of study. Those who have traced its development observe that rigorous, large-scale research on teacher education is difficult, time-consuming, and expensive to conduct; thus, some of the theoretical and methodological advances seen in more mature fields, for example, research on student learning, are just beginning to emerge in research on teacher education (Borko, Liston and Whitcomb, 2007, p. 3).

The objective of this article is to review research based on classroom strategies that can facilitate high school and freshman university chemistry teachers’ understanding of the nature of science, that is how scientists do science.

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Despite some controversy with respect to what constitutes the nature of science for science education, a certain degree of consensus has been achieved within the research

community with respect to the following aspects (Lederman et al., 2002; McComas et al., 1998; Niaz, 2001, 2008b, 2008c; Osborne, 2007; Osborne et al., 2003):

1) Scientific theories are tentative.

Scientific theories do not become laws even with additional evidence.

2) Scientific laws being epistemological constructions, do not describe the behavior of actual bodies, and thus many of our well known laws are ‘irrelevant’ (Blanco and Niaz, 1997; Giere, 1999).

3) Observations are theory-ladden.

4) Objectivity in science originates from a social process of competitive validation through peer review.

5) Science is not characterized by its objectivity but rather its progressive character (Lakatos, 1970, explanatory power).

6) Scientific progress is characterized by conflicts, competencies, inconsistencies and controversies among rival theories.

7) Scientists can interpret the same experimental data in different ways. 8) Scientists are creative and often resort to imagination and speculation.

9) There is no one way to do science and hence no universal step-by-step scientific method can be followed.

10) Scientific ideas are affected by their social and historical milieu.

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This section reviews research based on classroom strategies that can facilitate high school and university freshman teachers’ understanding of nature of science. All teachers participated in two Master’s level degree courses based on 34 readings related to nature of science, history, philosophy and epistemology of science (with special reference to controversial episodes). The two courses required 118 hours of classwork (formal presentations, question-answer sessions, written exams and critical essays). Some of the relevant units of the courses were the following: a) History and philosophy of science in the context of the development of chemistry (examples of some readings: Matthews, 1994; Niaz, 1998); b) Conceptual change in learning chemistry (examples of some readings: Niaz, 1995; Niaz et al., 2002); c) Nature of science (examples of some readings: Smith and Scharmann, 1999; Niaz, 2001); d) Critical evaluation of nature of science (examples of some readings: Lederman et al., 2002; Osborne et al., 2003). Results reported here are adapted from: Niaz, 2008b, 2008c.

Problematic Nature of the Scientific Method, Objectivity and the Empirical