Science teacher education on nature of science through explicit and reflective curriculum development

A convenience sample of prospective secondary science teachers enrolled in their Master’s degree education were explicitly and reflectively taught a concrete and specific NOS theme (investigations) through a mixed-method, instead of teaching several NOS themes or a very extensive one, as has been usual in other studies (Hanuscin, Lee & Akerson, 2011; Lederman, 2008; Tsai, 2007). The process included several curriculum and professional development activities (design, planning, creation, presentation, and discussion of teaching-learning sequences), which are a part of basic teacher education and involve group discussions and personal self-reflection on investigations. The impact of these activities on teachers’ understanding of investigations was assessed by a quantitative tool and the qualitative analysis of the reflective activities (Heering & Höttecke, 2014).

The quantitative assessments show that teachers' improvements on NOS understanding are clear, although modest and heterogeneous. Overall, most of the 190 assessment indicators of change (ten questions for nineteen teachers) are positive and represent an improvement, most of the teachers (10) reach a positive effect size mean, against a minority (3) who obtained a negative effect size mean. The results for the 10 assessment questions present a similar pattern, as most (5) achieve a positive effect size, a minority (3) achieve a negative effect size, and two have a zero effect size. These findings add to the growing body of knowledge that empirically supports the efficacy of explicit and reflective teaching methods for improving teachers’ NOS understanding (Akerson, Abd-el-Khalick & Lederman, 2000; Bell et al., 2011; Lederman, 2008).

However, when analyzing the complex heterogeneity of the teachers’ changes across questions and vice-versa, the study contributes a nuanced and detailed model of changes. The heterogeneity means that teachers’ changes simultaneously include some questions that improve and some that worsen their profile. In particular, the highest-progress teachers display some questions with a relevant negative effect size, and the lowest-progress teachers show some questions with a relevant positive effect size. Similarly, the questions achieving the highest mean positive changes involve teachers with high negative changes and the questions with the most negative changes involve teachers with high positive changes. The main consequence of these heterogeneous changes suggests that all the teachers partially improve their NOS beliefs but the improvement depends largely on the teacher and the question. Another finding concerning the change heterogeneity indicates that the assessment method can personalize teachers’ NOS progress across strengths and weaknesses (Cook & Buck 2013), which are different for each NOS issue (Cofré et al., 2019).

Another contribution is the significant relationship between teachers’ effectiveness to identify their changes on NOS beliefs (reflectivity) with the final and improvement indexes, which show that teachers with the highest self-reflection ability are probably the teachers with the highest improvement rates of NOS understanding. This finding suggests that developing some of the cognitive abilities involved in self-reflection (such as critical thinking and metacognition) may lead to greater progress on NOS understanding (Vázquez-Alonso & Manassero-Mas, 2018).

Altogether, the former findings should be interpreted within the context of the short time and modest experience carried out. First, the quantitative interpretation of improvements is limited to the comparisons that allow the data quantification scale, which is open to new analysis and different interpretations. Second, the intervention does not contain lecturing about NOS, and its time is shorter than in other studies, which usually last several months (Cofré et al., 2019; Deng et al., 2011) so that the modest effects of such a small intervention can be proportionally considered. Third, teachers’ changes suggest that the impact of the intervention is mixed and differential, as it seems to be heterogeneously endorsing some misinformed beliefs and weakening some adequate beliefs, instead of homogeneously promoting informed NOS beliefs (Cofré et al., 2019; Tsai, 2006). This irregular impact of treatments is also a challenge to improve its effectiveness, through explicitly reinforcing the informed ideas and disproving the misinformed ones through discussions (Abd-El-Khalick, 2012).

Another prospective contribution is the model developed for teaching NOS to pre-service science teachers, based on their professional development through NOS pedagogical competences such as planning NOS lessons, involving self-reflection and feedback from others, similar to Celik and Bayrakçeken (2006). The standardized model of tasks and the quantitative assessment of changes help to apply the model without instructors’ deep knowledge of NOS (Bennàssar et al., 2010; Manassero et al., 2016).

The teachers' qualitative reflection on their quantitative responses confirms the validity of teachers’ answers and deepens our understanding of the complexity of teachers' thinking about NOS (Abd-El-Khalick, 2012; Hanuscin et al., 2011). In addition, the quantitative assessment contributes to reducing the risk of idiosyncrasy, facilitates the inferential statistical analyses of teachers’ views, which is difficult with qualitative assessments (Brunner, Summers, Myers & Abd-El-Khalick, 2016), and allows standardized comparisons of experiences and researches (Abd-El-Khalick, 2012).

Some limitations of this study relate to the convenience sample of the participants and the short time of the intervention. We therefore recommend further studies with larger representative samples and deeper interventions. Moreover, the relationships between the lesson design and teachers’ NOS beliefs, and how the lesson development supports NOS understanding would be also worth studying. Finally, another limitation of the study, and simultaneously an opportunity for improvement, is methodological; the use of the questions’ average scores to represent teachers’ NOS conceptions is a limitation, as it is well known that the average statistic has a centralizing effect that sharply reduces the variability of the averaged data (in this case, the sentence indexes within each question). The opportunity stems from shifting the analysis of the pre-post differences from question average to sentence indexes, which conserve the entire data variability.

In sum, the explicit-reflective NOS model for teacher education presented herein contributes to the field through some findings: heterogeneous improvement of science teachers' understanding of NOS through reflection embedded in the professional development practices (pedagogy and design), standardized questionnaire-based assessment, quantitative and qualitative data and results, and inferential diagnosis of teachers’ weaknesses and strengths on NOS. Furthermore, the modest changes suggest proposals for improvement: making the personal reflection processes longer and deeper, deepening the specific pedagogical content knowledge of NOS (Burton, 2013; Mesci, 2020), and adding lecturing time to actively guide informed and misinformed NOS beliefs (Akerson, Morrison & Mcduffie, 2006).

Acknowledgements

Project EDU2015-64642-R funded by the Spanish State Research Agency and the European Regional Development Fund, European Union. On behalf of all the authors, the corresponding author states that there is no conflict of interest.