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Designing and interpreting controlled experiments are important inquiry skills addressed in many current science curricula. The relevant skills associated with the design and interpretation of controlled experiments are summarised under the term control-of-variables strategy (CVS). Research on elementary school students' CVS skills shows that they have basic conceptions of CVS, as they can correctly identify controlled experiments to test given hypotheses and can interpret the results of controlled experiments. However, they perform poorly when they have to plan experiments and interpret confounded experiments. Furthermore, previous research has identified eight misleading preconceptions regarding CVS that cause invalid experimental designs, called design errors. The current study investigates the occurrence and change of design errors during elementary school and their consistency over different tasks. Via a latent class analysis (LCA), we identified three distinct patterns of design errors: (1) correct CVS understanding, (2) change of too many variables and (3) non-contrastive experiments. Our results show that many students as low as grade two have a basic understanding of CVS and that occurring design errors are associated with limited metaconceptual knowledge about when and why to apply CVS. We discuss possible implications of our findings for teaching CVS and further research.

Science teachers should be able to notice student preconceptions in order to adapt instructions to their students' needs and support the learning process. Noticing as a core practice of teaching should thus be implemented early in science teacher education. A crucial prerequisite for noticing is knowledge about students' preconceptions, which is an important element of science teachers' pedagogical content knowledge. To enhance pre-service teachers' pedagogical content knowledge, flipped classroom approaches seem especially promising as they combine a theoretical introduction to important didactic concepts with a direct application of these concepts in profession-oriented learning tasks. Furthermore, flipped classrooms seem to satisfy the three basic personal needs of experience in competence, social relatedness, and autonomy according to the self-determination theory of motivation, thus enhancing learning. This intervention study investigates the effect of a course on physics didactics designed according to the flipped classroom approach on pre-service teachers' (N = 87) learning to notice student preconceptions. Specifically, we analyzed how pre-service teachers' perception of competence, social relatedness, and autonomy during course participation related to their noticing abilities. We found a significant increase (d = 0.40) in PSTs' noticing abilities, operationalized as absolute number of recognized preconceptions between pre- and posttest. However, this increase was not mediated by PSTs' perception of competence, social relatedness, and autonomy.

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.

Floating and sinking (FS) is a key topic in science education, both at primary and secondary levels. The interpretation of FS phenomena, however, is challenging due to the difficulty of the scientific concepts and explanatory models involved (e.g., density, buoyancy), along with students' everyday experiences, which conflict with scientific explanations. Consequently, many studies over the last few decades have investigated how FS could be taught effectively to students of different ages while utilizing multiple teaching approaches. This meta‐analysis summarizes findings from 69 intervention studies on teaching FS conducted between 1977 and 2021. Over all studies, we estimated a mean effect size of g = 0.85 (95% CI = 0.71, 0.99). This large effect size demonstrates that, although FS is a challenging concept, teaching FS is effective even in elementary school. Moreover, in a moderator analysis, we investigate the effect of intervention characteristics, students' age, as well as study design, and assessment features on the mean study effect size. To analyze the effect of these moderator variables, we use a three‐level hierarchical meta‐regression model for dealing with multiple effect sizes from single studies. We found two intervention characteristics that explain variance in study effect sizes: longer lasting interventions result in larger effect sizes and interventions where hands‐on experiments are applied are more effective than those utilizing virtual experiments. Furthermore, studies with a treatment‐control group comparison have significantly smaller effect sizes than studies with a pre‐post design. We discuss the implications of our findings regarding the moderator variables for effective teaching of FS and further research on FS. [ABSTRACT FROM AUTHOR]

The ability to design and interpret controlled experiments is an important scientific process skill and a common objective of science standards. Numerous intervention studies have investigated how the control-of-variables-strategy (CVS) can be introduced to students. However, a meta-analysis of 72 intervention studies found that the opportunity to train CVS skills with hands-on tasks (g = 0.59) did not lead to better acquisition of CVS relative to interventions without a hands-on component (g = 0.74). We conducted an intervention study in which we investigated the differential effects of hands-on and paper-and-pencil training tasks on 161 eighth-grade students' achievement. CVS was demonstrated to all students before they were grouped into a hands-on or a paper-and-pencil training condition. In both training conditions, students designed and interpreted experiments about which variables influence the force of electromagnets. Students in the hands-on group interacted with physical equipment while students in the paper-and-pencil group planned experiments using sketches and interpreted the outcome of experiments presented in photographs. We found no general advantage or disadvantage of hands-on tasks, as both groups did equally well on CVS and content knowledge tests. However, hands-on students outperformed paper-and-pencil students on a hands-on test identical to the training tasks, whereas the paper-and-pencil students outperformed hands-on students on a science fair poster evaluation task similar to the paper-and-pencil training. In summary, students learned task-specific procedural knowledge, but they did not acquire a deeper conceptual understanding of CVS or the content domain as a function of type of training. Implications for instruction and assessment are discussed.

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.