Abstracts - Earli

that the instructional design difficulty has to be taken into account when examining the influenceof motivational learner prerequisites on mental effort.Understanding of chemical and physical change: a study with pre-service teachersIngrid Martorell, University of Lleida (UdL), SpainManoli Pifarre, University of Lleida (UdL), SpainSusana Godia, University of Lleida (UdL), SpainAnna Gene, University of Lleida (UdL), SpainUnderstanding the distinction between physical change and chemical change is a basic conceptthat is important for the understanding of chemistry (Solsana, et al., 2003). Students havehistorically showed poor understanding of chemical and physical change. The main goal of thiswork is to design, implement and evaluate an instructional approach for science pre-serviceteachers to help them move towards a conceptual understanding of physical change and chemicalchange. A detailed description of the instructional approach is presented. Preliminary resultsshowed that post test scores are significantly higher than pre test ones (t=-4,14; p=0,001, n=20).Qualitative assessments indicate that students in the post test improve in writing scientificexplanations and referred correctly to some difficult concepts like matter, energy, reversibility,chemical reaction, dissolution, and macroscopic and microscopic level.Plotting effective instruction: Context-specific relationships between instruction and gains inreading comprehensionStuart McNaughton, University of Auckland, New ZealandMeaola Amituanai-Toloa, University of Auckland, New ZealandShelley MacDonald, University of Auckland, New ZealandMei Kuin Lai, University of Auckland, New ZealandSasha Farry, University of Auckland, New ZealandGenerally we know what makes good comprehenders and features of effective teaching of readingcomprehension. But idiosyncratic needs exist for effective teaching and learning in particularinstructional contexts. We plot relationships between teaching and achievement over two largescale three year interventions in two clusters of seven schools serving minority communities (120teachers and 3000 students). Classroom observation and achievement data were collected within aquasi experimental design. Relationships between teachers’ behaviour and achievement, and casestudies of highly effective and less effective classrooms are used to show that attributes ofteaching, including increased focus on vocabulary, on checking text meanings, and on students’awareness of strategies and tasks, were related to specific areas of comprehension. The patternsillustrate the claims about context specific needs.Soliciting versus providing explanations of worked examplesZane Olina, Florida State University, USAXiaoxia Huang, Florida State University, USARobert Reiser, Florida State University, USAThe study involving 150 American middle school students in an instructional program aboutcomma rules examined two strategies, instructional explanations and self-explanation prompts, formaximizing learning from worked examples. Previous research has shown that worked examplesare more effective during initial stages of skill acquisition than conventional problems, yetstandard worked examples often fail to facilitate transfer. Several studies focusing on enhancing– 752 –