Supporting students' construction of scientific explanation through curricular scaffolds and teacher instructional practices.

An essential goal of classroom science is to help all students become scientifically literate to encourage greater public understanding in a science infused world. This type of literacy requires that students participate in scientific inquiry practices such as construction of arguments or scientific explanations in which they justify their claims with appropriate evidence and reasoning. Although scientific explanations are an important learning goal, this complex inquiry practice is frequently omitted from k-12 science classrooms and students have difficulty creating them. I investigated how two different curricular scaffolds (context-specific vs. generic), teacher instructional practices, and the interaction between these two types of support influence student learning of scientific explanations. This study focuses on an eight-week middle school chemistry curriculum, How can I make new stuff from old stuff?, which was enacted by six teachers with 578 students during the 2004-2005 school year. Overall, students' written scientific explanations improved during the unit in which they were provided with multiple forms of teacher and curricular support. A growth curve model of student learning showed that there was a significant difference in the effect of the two curricular scaffolds towards the end of the unit and on the posttest. The context-specific scaffolds resulted in greater student learning of how to write scientific explanations, but only for three of the six teachers. The case studies created from the videotapes of classroom enactments revealed that teachers varied in which instructional practices they engaged in and the quality of those practices. Analyses suggested that the curricular scaffolds and teacher instructional practices were synergistic in that the supports interacted and the effect of the written curricular scaffolds depended on the teacher's enactment of the curriculum. The context-specific curricular scaffolds were more successful in supporting students in this complex task only when teachers' enactments provided generic support for scientific explanation through instructional practices. For teachers who did not provide their students with generic support, neither curricular scaffold was more effective. Classrooms are complex systems in which multiple factors and the interactions between those factors influence student learning.PhDEducationScience educationUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/126234/2/3238032.pd