Leon Cooper’s Perspective on Teaching Science: An Interview Study

The authors of this paper portray the perspective of Professor Leon Cooper, a theoretical physicist, Nobel laureate, active researcher, and physics textbook author, on teaching science and on the nature of science (NOS). The views presented emerged from an interview prepared by the authors and responded to in writing by Professor Cooper. Based on the gathered data and the subsequent interpretation of it, the authors identified several educational implications and drew the following conclusions: (a) science should be taught within an historical perspective; (b) textbook authors generally have an empiricist epistemology which makes their presentation of science difficult to understand; (c) an historical perspective inevitably involves comparing, contrasting, and scrutinizing different historical accounts of the same events; (d) varying interpretations of observations do not undermine the objective nature of science; (e) new ideas in physics comprise an imposed vision of the world, and these ideas are then slowly accepted by the scientific community; (f) the current view in any science is almost always a mixture of data, hypotheses, theoretical ideas, and conjectures; (g) since experiments are difficult to perform and understand, scientists rely on their presuppositions to guide the integration of data, theory, and conjectures; (h) inconsistencies in the construction of theories can facilitate new theoretical ideas; and (i) case studies based on various experiments show that scientists use intuition which is guided by facts, conjectures, and speculations.     

Evaluation of Oxidative Stress and DNA Damage in Benign Prostatic Hyperplasia Patients and Comparison with Controls

In the present study, oxidative stress and lymphocytic DNA damage in both pre-op and post-op benign prostrate hyperplasia (BPH) patients with age >50 years was evaluated and compared with normal healthy subjects (controls- without any evidence of disease) of the same sex and age group. From December 2007 to November 2009, oxidative stress in 45 BPH patients were evaluated both before (pre-op patients) and after 7 days of surgery (post-op patients) in terms of measurements of plasma levels of (1) various anti-oxidative enzymes, (2) non-enzymatic antioxidants and (3) malondialdehyde which is a product of lipid peroxidation. The lymphocyte DNA damage was also evaluated by single cell alkaline gel electrophoresis in terms of tail length migration in these patients. These values were compared with their respective control subjects of similar sex and age group. The activities of antioxidant enzymes and the levels of antioxidant, reduced glutathione were found significantly decreased (p < 0.05) in serum samples of pre-operative group of BPH patients as compared to the controls. These altered parameters increased significantly (p < 0.05) and returned to their near normal control values, but not up to baseline values, in post operative patients i.e. after the cancer load was decreased by surgery. Lymphocytic DNA damage was found to be significantly increased in pre-op group as compared to controls and was reduced after surgery in post-op group. The present study therefore, shows significantly increased levels of oxidative stress and DNA damage in BPH patients which were reduced after removal of tumour load. Thus oxidative damage plays an important role in prostate tumourogenesis and timely management of oxidative stress can be of importance in preventing the occurrence of BPH.     

Investigating the effectiveness of a POE-based teaching activity on students’ understanding of condensation

This article reports on the development of a Predict–Observe–Explain, POE-based teaching strategy to facilitate conceptual change and its effectiveness on student understanding of condensation. The sample consisted of 52 first-year students in primary science education department. Students’ ideas were elicited using a test consisting of five probe questions and semi-structured interviews. A teaching activity composed of three Predict–Discuss–Explain–Observe–Discuss–Explain (PDEODE) tasks was employed, based on students’ preconceptions identified with the test. Conceptual change in students’ understanding of condensation was evaluated via a pre-, post-, and delayed post-test approach and students’ interviews. Test scores were analyzed using both qualitative and quantitative methods. The findings suggested that the strategy helps students to achieve better conceptual understanding for the concept of condensation and enables students to retain these new conceptions in their long-term memory.     

Achievement in Science as a Function of the Mobility—Fixity Dimension

The characteristic of field‐independent subjects to function consistently in a field‐independent fashion (i.e. fixity) and of others to vary more according to circumstances (i.e. mobility) has been referred to as the Mobility‐Fixity Dimension. This dimension, based on the theories of Werner, Witkin and Pascual‐Leone suggests, that field mobile students perform better than fixed students in science courses. The main objective of this study, based on high school students (mean age = 16.5 years; SD = 1.0) in Venezuela, was to test the following predictions. (1) Mobile students would obtain a better performance than fixed students on variables such as introductory high school mathematics, physics, chemistry, biology and earth science courses; and (2) among mobile students, those classified in the middle‐high range of the Group Embedded Figures Test (GEFT) and the Figural Intersection Test (FIT), would obtain a better performance as compared to those in the lower‐middle range. Results obtained, in general, provide support for the first prediction. The differences between the performances of mobile and fixed groups were, however, significant (p < 0.05) only for the biology and earth science courses. Students in one of the high mobility groups obtained a better performance (in all courses) than not only the corresponding low mobility group but also a fixed group with high scores on both the GEFT and FIT, which provides support for the second prediction. It is concluded that problem‐solving ability in science courses may be strengthened through the mediation of the Mobility‐Fixity Dimension.     

Manipulation of M demand of chemistry problems and its effect on student performance: A neo-piagetian study

It has been shown that student performance in chemistry problems decreases as the M demand of the problem increases, thus emphasizing the role of information processing in problem solving. It was hypothesized that manipulation (increase or decrease) of the M demand of a problem can affect student performance. Increasing the M demand of a problem would affect more the performance of subjects with a limited functional M capacity. The objective of this study is to investigate the effect of manipulation (increase) of the M demand of chemistry problems, having the same logical structure, on performance of students having different functional M capacity, cognitive style, and formal operational reasoning patterns. As predicted the performance of one group of students was lower after the manipulation (increase) in the M demand of the problem. This shows how even small changes in the amount of information required for processing can lead to working memory overload, as a consequence of a poor capacity for mobilization of M power.     

Facilitating Chemistry Teachers’ Understanding of Alternative Interpretations of Conceptual Change

Historians and philosophers of science have recognized the importance of controversies in the progress of science. The objective of this study was to facilitate in-service chemistry teachers’ understanding of conceptual change based on alternative philosophical interpretations (controversies). Selected controversies formed part of the chemistry curriculum both at secondary and university freshman level. The study is based on 17 in-service teachers who had registered for all week course on “Investigation in the Teaching of Chemistry” as part of their Master’s degree program. The course is based on 17 readings drawing on a history and philosophy of science perspective with special reference to controversial episodes. Course activities included written reports, class room discussions based on participants’ presentations, and written exams. A major finding of this study is that most teachers went through an experience that involved: inconsistencies, conflicts, contradictions, and finally some degree of conceptual change. A few of the participants resisted any change, but still raised important issues with respect to conceptual change. Some of the educational implications are: a) Similar to a scientist, a student can live with two rival theories simultaneously and as the student enriches his cognitive repertoire the conflict can perhaps be resolved; b) Resolution of a conflict may not follow a logical pattern of reasoning but rather a slow process (based on motivational, intuitive, and affective factors) in which the hardcore of beliefs slowly crumbles; c) In science there is no absolute truth, nor a scientific method and consequently there cannot be rules, methods, algorithms, or pre-determined steps for introducing conceptual change; d) Teachers’ epistemological outlook is crucial in order to facilitate conceptual change.     

A Reconstruction of Structure of the Atom and Its Implications for General Physics Textbooks: A History and Philosophy of Science Perspective

Recent research in science education has recognized the importance of history and philosophy of science. The objective of this study is to evaluate the presentation of the Thomson, Rutherford, and Bohr models of the atom in general physics textbooks based on criteria derived from history and philosophy of science. Forty-one general physics textbooks (all published in the United States) were evaluated on two criteria based on Thomson's work, three on Rutherford's work, and three on Bohr's work. Results obtained show that general physics textbooks do not systematically include a history and philosophy of science perspective. Most textbooks present an inductivist perspective in which experimental details are considered to be paramount. On the contrary, a historical reconstruction of the experimental details inevitably includes: the context in which an experiment is conducted, the theoretical framework that guides the scientist, and alternative interpretations of data that lead to conflicts and controversies. Examples are provided to show how historical reconstructions of atomic models can provide students an opportunity to appreciate how scientists work and science progresses. It is plausible to suggest that textbook presentations based on a history and philosophy of science perspective can perhaps arouse students' interest in the subject and hence lead to greater conceptual understanding.     

A rational reconstruction of the kinetic molecular theory of gases based on history and philosophy of science and its implications for chemistry textbooks

Research in science education has recognized the importance of history and philosophy of science. Given this perspective, the study was designed to develop a framework for examining the way in which chemistry textbooks describe the kinetic theory and related issues. The framework was developed by a rational reconstruction of the kinetic molecular theory of gases based primarily on the interpretations of Maxwell and Boltzmann, by historians and philosophers of science. Another aspect of the framework was based on an analysis of freshman chemistry students' performance on gas problems that required the use of algorithms or conceptual understanding. Subsequently, 22 textbooks were evaluated using a framework consisting of six criteria. Results obtained showed that most textbooks lacked a history and philosophy of science framework and did not deal adequately with the following aspects: (1) Postulates of the kinetic theory were speculative and played the role of simplifying assumptions, considered to be the rule in science rather than being the exceptions; (2) Based on these simplifying assumptions, the theorists built a series of tentative models that progressively incorporated the behavior of real gases; (3) Similar to other research programs in the history of science, Maxwell's was based on inconsistent foundations; (4) Development of the kinetic theory had to compete with chemical thermodynamics, a rival research program; (5) Maxwell and Boltzmann facilitated our understanding of gas behavior beyond the observable hydrodynamical laws, by explaining the internal properties (e.g., molecular collisions).     

Progressive transitions in chemistry teachers’ understanding of nature of science based on historical controversies

The objective of this study is to facilitate progressive transitions in chemistry teachers understanding of nature of science in the context of historical controversies. Selected controversies referred to episodes that form part of the chemistry curriculum both at secondary and university freshman level. The study is based on 17 in-service teachers who had registered for an 11-week course on ‘Investigation in the teaching of chemistry’ as part of their Master’s degree program. The course is based on 17 readings drawing on a history and philosophy of science perspective with special reference to controversial episodes in the chemistry curriculum. Course activities included written reports, class room discussions based on participants’ presentations, and written exams. Based on the results obtained it is suggested that 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 basis of science; (b) Myths associated with respect to the nature of science and teaching chemistry; (c) Science does not develop by appealing to objectivity in an absolute sense, as creativity and presuppositions also play a crucial role; (d) The role of speculation and controversy in the construction of knowledge based on episodes from the chemistry curriculum; (e) How did Bohr confirm his postulates? This goes beyond the treatment in most textbooks; (f) Differentiation between the idealized scientific law and the observations. It is concluded that given the opportunity to reflect, discuss and participate in a series of course activities based on various controversial episodes, teachers’ understanding of nature of science can be enhanced.