Investigating factors affecting students’ performance to PISA Science items

The present paper aims to investigate, on the one hand, the extent to which PISA Science items validly assess the knowledge and skills of 15 year-old Greek students, while, on the other hand, to examine the effect of the following factors: student’s gender, scientific processes and contexts (situations) on the students’ performance in these PISA items. The research used paper-and-pencil test with published PISA Science items, conducted individual semi-structured interviews with 15 year-old students and finally marked the students’ responses, according to the PISA marking guide. Τhe basic finding resulting from the data analysis is that the paper-and-pencil test with the PISA Science items does not tend, unlike the interview, to effectively record the Greek students’ Science knowledge and skills. Moreover, the analysis revealed that the performance of students in the PISA Science items (paper-and-pencil test and interview) tend to be independent of the student’s gender and depend on the context in which the knowledge and processes are assessed. Additionally, the possible correlation between the students’ performance and the factor of scientific processes seems to depend on the setting in which the students provide their responses (paper-and-pencil test or interview)

Teachers' pictorial representations of the scientist

Research concerning the conceptions of non-experts (mainly students and teachers) about the nature of science has focused over the last decades on their images of scientists. Specifically, studies concentrating on teachers' relevant conceptions are particularly critical, since their images of scientists affect their teaching practices, forming a 'hidden curriculum'. Thus, the teachers who adopt stereotypical images of scientists and their activity are likely to induce negative attitudes towards science and scientists to students, which in turn affect the students' future personal, professional and social aspirations. The study presented in this chapter aims at determining a) the extent to which Greek teachers adopt a stereotypical model of the scientist and b) the types of activities they consider to be scientific. The sample consisted of 240 teachers, either pre-service, or in-service (primary, secondary, tertiary, and vocational education teachers). The method used draws on the 'DAST' ('Draw-A-Scientist-Test') technique ('DAST', Chambers, 1983; She, 1998). The participants were originally asked to individually draw a male or female scientist in their workplace and subsequently to produce a second drawing representing a scientist of the opposite sex. The analysis of the collected data indicates that the teachers hold stereotypic images of scientists. Moreover, a variety of activities (relevant to science, as well as to medicine, teaching, informatics, or law) are considered by them as scientific. Furthermore, interesting differentiations appear in the stereotypic model of the scientist according to teachers' sex, represented scientist's sex, type of scientific activity, and teachers' professional status (pre-service or in-service, and level of education they are employed in). The discussion of the results allows for valuable conclusions and implications for teacher education aiming at inspiring a more appropriate, meaningful and egalitarian image of science and scientists as well as improving teachers' attitudes towards them. © 2009 Nova Science Publishers, Inc. All rights reserved

Teaching chemistry concepts through multiple analogies

One of the most important challenges faced in science teaching is students' preexisting conceptions about the concepts and phenomena they are taught. These conceptions typically diverge from school science and should be taken into consideration by science teachers when negotiating the construction of scientific knowledge in the classroom. Analogies are a particularly powerful tool for science teaching, since they allow comparison and mapping between different knowledge domains: the source (a domain familiar to the learner) and the target (the domain to be taught and understood by the learner), thus supporting the construction of new knowledge. This study proposes an introductory chemistry teaching sequence about the concepts of chemical element and chemical compound by means of multiple analogies, designed so as to take into account students' alternative conceptions. An experimental design involving pretests and posttests with two groups of eigth grade students attending a public secondary school in Greece was implemented, comprising a teaching intervention using multiple analogies with the experimental group and a conventional approach with the control group. Results indicate that the participants in the experimental group achieved significantly higher scores in the posttest than their counterparts in the control group. Their responses reflected a significant improvement in their understanding of critical aspects of the taught concepts, concerning the distinction between chemical element and chemical compound as well as between chemical compound and mixture. Moreover, they exhibited a better understanding of a variety of characteristic properties of matter. Implications for teaching of fundamental chemistry concepts with the use of multiple analogies are discussed. © Common Ground Research Networks, Vasilia Christidou, Marianna Theodosiou, Vassilia Hatzinikita