Hendrik Härtig

The impact of sub-skills and item content on students’ skills with regard to the control-of-variables strategy

ABSTRACT The so-called control-of-variables strategy (CVS) incorporates the important scientific reasoning skills of designing controlled experiments and interpreting experimental outcomes. As CVS is a prominent component of science standards appropriate assessment instruments are required to measure these scientific reasoning skills and to evaluate the impact of instruction on CVS development. A detailed review of existing CVS instruments suggests that they utilize different, and only a few of the four, critical CVS sub-skills in the item development. This study presents a new CVS assessment instrument (CVS Inventory, CVSI) and investigates the validity of student measures derived from this instrument utilizing Rasch analyses. The results indicate that the CVSI produces reliable and valid student measures with regard to CVS. Furthermore, the results show that the item difficulty depends on the CVS sub-skills utilized in item development, but not on the item content. Accordingly, previous instruments that are restricted to a few CVS sub-skills tend to over- or underestimate students’ CVS skills. In addition, these results indicate that students are able to use CVS as a domain general strategy in multiple content areas. Consequences for science instruction and assessment are discussed.

The Terminology within German Lower Secondary Physics Textbooks

From primary school through university and beyond, textbooks are crucial for teaching and learning science. In most cases the content of the books is aligned with intended state curricula, and teachers in many countries use textbooks at least to guide lesson preparation. Therefore, textbooks are discussed as an implemented curriculum. Many existing studies have been conducted on the content of science textbooks. Using different methods, Biology textbooks as well as Physics textbooks could be shown to be not very coherent in sense of using striking scientific terms regularly. However from the viewpoint of learning only the frequent use of a term will elicit stable propositions around the term, which allows emerging concepts associated with the terms in the mental representation of the readers.

Making inquiry-based science learning visible: the influence of CVS and cognitive skills on content knowledge learning in guided inquiry

ABSTRACT Many science curricula and standards emphasise that students should learn both scientific knowledge and the skills associated with the construction of this knowledge. One way to achieve this goal is to use inquiry-learning activities that embed the use of science process skills. We investigated the influence of scientific reasoning skills (i.e. conceptual and procedural knowledge of the control-of-variables strategy) on students’ conceptual learning gains in physics during an inquiry-learning activity. Eighth graders (n = 189) answered research questions about variables that influence the force of electromagnets and the brightness of light bulbs by designing, running, and interpreting experiments. We measured knowledge of electricity and electromagnets, scientific reasoning skills, and cognitive skills (analogical reasoning and reading ability). Using structural equation modelling we found no direct effects of cognitive skills on students’ content knowledge learning gains; however, there were direct effects of scientific reasoning skills on content knowledge learning gains. Our results show that cognitive skills are not sufficient; students require specific scientific reasoning skills to learn science content from inquiry activities. Furthermore, our findings illustrate that what students learn during guided inquiry activities becomes visible when we examine both the skills used during inquiry learning and the process of knowledge construction. The implications of these findings for science teaching and research are discussed.