Abstracts - Earli

from the assumption that all three observable features of constructivist instruction are importantfor learning success, we examined to what extent they were realised simultaneously in thevideotaped instruction, and how this affected the students’ learning and the assessment ofinstructional quality. For this purpose, (1) low-inferent codings measured the extent to which thethree features of constructivist instruction were realised in the instructional units, with groupsformed based on different feature constellations. (2) Links between the feature constellations andassessment of instructional quality through high-inferent expert ratings were examined usinganalyses of variance, and (3) effects on the cognitive outcomes were investigated usinghierarchical linear modelling. The results indicate that a low degree of all three features negativelyinfluences learning success, whereas a positive extent of one or more features can be assumed tohave compensation or substitution effects.B 128 August 2007 17:30 - 18:50Room: 0.89 JedlikPaper SessionConceptual changeChair:Mary Dawn Ainley, University of Melbourne, AustraliaDivide and Conquer: How children acquire more advanced numerical representationsElida Laski, Carnegie Mellon University, USARobert S. Siegler, Carnegie Mellon University, USADespite the importance of understanding the relative magnitude of numbers, little is known abouthow this understanding develops. I will describe the results of a recent experiment thatdemonstrates a causal role of categorization in eliciting changes in numerical representations. Theresults indicated that kindergartners who were provided feedback that encouraged sorting thenumbers between 0 and 100 into five equal size categories generated more linear estimates ofnumerical magnitude than kindergartners who were provided identical sorting instructions andpractice but no feedback. Reasons for why improved categorization of numbers promotes linearrepresentations and potential implications for instruction will be discussed.The construction of scientific explanations and its effect on student learningMaria Araceli Ruiz-Primo, University of Colorado at Boulder, USAMin Li, University of Washington, USAShin Ping Tsai, University of Washington, USAOne fundamental activity in scientific inquiry is the construction of scientific explanations. It isassumed that construction of explanations helps students understand the nature of scientificknowledge in terms of its connection to evidence and its uncertainty and subjectivity to change. Inthis paper, we analyze the quality of students’ written explanations in eight middle-schoolclassrooms and explore the link between the quality of students’ written explanations and theirperformance on assessments focusing on the topic studied. More specifically, we asked whetherthe quality of the students’ written explanations found in the students’ science notebooks was– 71 –