Teachers' professional knowledge is considered one of the most important predictors of instructional quality. According to Shulman, such professional knowledge includes content, pedagogical content and pedagogical knowledge. Although recent research shed some light on the structure of the dimensions of professional knowledge, little is known how teacher education impacts pre-service physics teachers' professional knowledge. In an effort to address this issue, we examined the content, pedagogical content and pedagogical knowledge of N = 200 pre-service physics teachers enrolled in different years of teacher education at 12 major teacher education universities in Germany. We used structural equation modelling (1) to examine the relations amongst pre-service physics teachers' content, pedagogical content and pedagogical knowledge, (2) to explore how the three kinds of knowledge and their relations differ across different stages of teacher education and (3) to identify factors affecting the level of each component of professional knowledge. Our findings suggest that content, pedagogical content and pedagogical knowledge represent distinct types of knowledge. Furthermore, our findings show that in the first years of professional education, pedagogical content knowledge is more closely related with general pedagogical knowledge while in later years, it is more closely related with content knowledge, suggesting that it develops from a general knowledge about teaching and learning into knowledge about the teaching and learning of specific content. Finally, beyond school achievement and years of enrolment as predictors, we find in particular the amount of classroom observations to have a positive impact on the professional knowledge of pre-service physics teachers. ARTICLE HISTORY

Olaf Lechtenfeld and Stefan PetersenInstitut für Theoretische Physik, Universität Hannover Appelstraße 2, 30167 Hannover, Germany E-mail: lechtenf@itp.uni-hannover. de, petersen@itp.uni-hannover.de Abstract: Noncommutative multi-solitons are investigated in euclidean two-dimensional U(n) and grassmannian sigma models, using the auxiliary Fock-space formalism. Their construction and moduli spaces are reviewed in some detail, unifying abelian and nonabelian configurations. The analysis of linear perturbations around these backgrounds reveals an unstable mode for the U(n) models but shows stability for the grassmannian case. For multi-solitons which are diagonal in the Fock-space basis we explicitly evaluate the spectrum of the hessian and identify all zero modes. It is very suggestive but remains to be proven that our results qualitatively extend to the entire multi-soliton moduli space.

This study presents findings on the physics identity development of female students in the German Physics Olympiad who participated in an intervention designed to support their engagement in physics. Enrichment programs such as the Physics Olympiad have been found to positively impact students' engagement and intent to pursue a career in science. However, many enrichment programs, including the Physics Olympiad, suffer from an underrepresentation of young women. The intervention investigated in this study capitalizes on gender-related research in physics education in order to explore ways in which gender equity can be raised in enrichment programs. To this end, we designed an identity-safe learning environment that facilitates participating young women's physics identity development. For example, same-sex groupings and considerately adopted physics contents that particularly acknowledge young women's interests (e.g., relation to medical issues and the human body) were utilized. Overall, 30 Olympians took part in a one-day intervention (13 females, 17 males). Positive effects in two important physics identity constructs, namely, interest and competence, for young women were found, while at the same time no effects were found for young men. Furthermore, the young women were more likely to participate in next year's Physics Olympiad, compared to the overall female Physics Olympiad population. These results indicate that the careful design of an intervention based on gender research and science identity theory can support young women's physics identity development.

The relevance of the study capacity for success in introductory physics courses Abstract Physics courses at German universities show above-average drop-out rates. Yet there is little empirical evidence concerning characteristics, which facilitate academic success. Based on theoretical considerations and empirical findings regarding the influence of cognitive and content-specific characteristics of the study capacity on academic success, this study surveyed N = 158 freshmen at a German University. The influence of the predictors on the probability to succeed in the exam was evaluated using logistic regressions. It was found, that with the final school exam grade and the last physic grade the success of 87 % of the participants could be classified correctly. The prior physics knowledge however didn't improve this prediction. Looking at the examination grades of the successful participants using multiple linear regressions, the prior physics knowledge was the only significant predictor. So differences in the prior knowledge could be compensated to a certain degree during the first semester. To support all students in an optimal manner the existing supporting arrangements like tutorials or preparatory courses need to be extended beyond discussing only physics content.

Student competitions can act as potent enrichment measures and complement formal schooling in fostering students’ motivation as well as promoting their skills. This article presents the German Physics Olympiad, the national precursor to the International Physics Olympiad, in the general context of student competitions in Germany and its integration with the so called Science Olympiads in Germany. To put the German Physics Olympiad into an international context its structure and some of its features are compared with data on Physics Olympiads in other countries. As an outlook we elaborate on some of the challenges the Physics Olympiad in Germany is facing and present two research projects that further support the development of the competition.