A STUDY OF CHANGES IN MIDDLE SCHOOL TEACHERS UNDERSTANDING OF SELECTED IDEAS IN SCIENCE AS A FUNCTION OF AN IN-SERVICE PROGRAM FOCUSING ON STUDENT PRECONCEPTIONS

This article examines the impact of a specially designed in-service mo del on teacher understanding of selected science concepts. The underly ing idea of the model is to get teachers to restructure their own unde rstanding of a selected science topic by having them study the structu re and evolution of their students' ideas on the same topic. Concepts on topics from the life, earth, and physical sciences served as the co ntent focus and middle school Grades 4-9 served as the context for thi s study. The in-ser-vice experience constituting the main treatment in the study occurred in three distinct phases. In the initial phase, pa rticipating teachers interviewed several of their own students to find out what kinds of preconceptions students had about a particular topi c. The teachers used concept mapping strategies learned in the in-serv ice to facilitate the interviews. Next the teachers teamed with other teachers with similar topic interests and a science expert to evaluate and explore the scientific merit of the student conceptual frameworks and to develop instructional units, including a summative assessment during a summer workshop. Finally, the student ideas were further eval uated and explored as the teachers taught the topics in their classroo ms during the fall term. Concept maps were used to study changes in te acher understanding across the phases of the in-service in a repeated- measures design. Analysis of the maps showed significant growth in the number of valid propositions expressed by teachers between the initia l and final mappings in all topic groups. But in half of the groups, t his long-term growth was interrupted by a noticeable decline in the nu mber of valid propositions expressed. In addition, analysis of individ ual teacher maps showed distinctive patterns of initial invalid concep tions being replaced by new invalid conceptions in later mappings. The combination of net growth of valid propositions and the patterns of e volving invalid conceptions is discussed in constructivist terms.