No abstract

The integration of scientific modeling into science teaching is key to the development of students’ understanding of complex scientific phenomena, such as genetics. With this in mind, we conducted an introductory hands-on module during an outreach gene technology laboratory on the structure of DNA. Our module examined the influence of two model evaluation variants on cognitive achievement: Evaluation 1, based on students’ hand-drawn sketches of DNA models and two open questions, and evaluation 2, based on students’ own evaluations of their models in comparison to a commercially available DNA model. We subsequently subdivided our sample (N = 296) into modellers-1 (n = 151) and modellers-2 (n = 145). Analyses of cognitive achievement revealed that modellers-2 achieved higher scores than modellers-1. In both cases, low achievers, in particular, benefitted from participation. Assessment of modellers-2 self-evaluation sheets revealed differences between self-evaluation and independent reassessment, as non-existent model features were tagged as correct whereas existent features were not identified. Correlation analyses between the models’ assessment scores and cognitive achievement revealed small-to-medium correlations. Consequently, our evaluation-2 phase impacted students’ performance in overall and model-related cognitive achievement, attesting to the value of our module as a means to integrate real scientific practices into science teaching. Although it may increase the workload for science teachers, we find that the potential scientific modeling holds as an inquiry-based learning strategy is worth the effort.

No abstract

As effective methods to foster students’ understanding of scientific models in science education are needed, increased reflection on thinking about models is regarded as a relevant competence associated with scientific literacy. Our study focuses on the influence of model-based approaches (modeling vs. model viewing) in an out-of-school laboratory module on the students’ understanding of scientific models. A mixed method design examines three subsections of the construct: (1) students’ reasoning about multiple models in science, (2) students’ understanding of models as exact replicas, and (3) students’ understanding of the changing nature of models. There were 293 ninth graders from Bavarian grammar schools that participated in our hands-on module using creative model-based tasks. An open-ended test item evaluated the students’ understanding of “multiple models” (MM). We defined five categories with a majority of students arguing that the individuality of DNA structure leads to various DNA models (modelers = 36.3%, model viewers = 41.1%). Additionally, when applying two subscales of the quantitative instrument Students’ Understanding of Models in Science (SUMS) at three testing points (before, after, and delayed-after participation), a short- and mid-term decrease for the subscale “models as exact replicas” (ER) appeared, while mean scores increased short- and mid-term for the subscale “the changing nature of models” (CNM). Despite the lack of differences between the two approaches, a positive impact of model-based learning on students’ understanding of scientific models was observed.

DNA-modeling boxes (see Fig. 2) One-way drinking cups (foodsafe) Water bottle (foodsafe) with distilled water Small beakers with color solution (e.g., water with blue food coloring or ink) and empty white Eppendorf tube Plastic Pasteur pipettes (3 ml; sterile sealed) Pipette pumps (e.g., Karter Scientific Labware Manufacturing) Snap-cap vials (20 ml; clean and dry) (e.g., Resch Glas) Tweezers (clean and dry) Black placemats (e.g., laminated color paper) Centrifuge Linear pipettor stand with 6 micropipettes (two 1,000 ml, two 200 ml, two 20 ml) (e.g., Eppendorf) Racks with pipette tips in two sizes (sterilized; e.g., blue and yellow) Rack filled with Eppendorf tubes (all sterilized; filled with adequate reagents: 2 white, 2 green, 2 blue, 2 red; and 6 closed, empty Eppendorf tubes marked with "1, 2, 3" for each group) (see Table 3 for filling) Styrofoam box with ice cubes (ice bath) for storing the isopropyl alcohol snapcap vial (P) and 2 Eppendorf tubes with isopropyl alcohol (yellow)