Introduction

Scientific literacy is a primary aim for science education in the 1980's. An important component of scientific literacy is an adequate conception of the nature of science. Three decades of research on students' conceptions of the nature of science-the values, assumptions, and processes upon which scientific knowledge is based-have given us little more than the knowledge that we are unhappy with the conceptions possessed by our students. Researchers have assumed that a significant positive relationship exists between teachers' conceptions and changes in students' conceptions. This assumption has remained virtually untested.

The initial purpose of this research was to assess the validity of the assumption that teachers' and students' conceptions are significantly related. Secondly, and most importantly, this research identifies classroom variables that are related to changes in students' conceptions of science.

Method

For this study 18 senior high school biology teachers and their students were selected randomly from nine public schools. All instruction followed the New York State Regents biology syllabus which is college preparatory in its orientation. Both teachers and students were tested on the "Nature of Scientific Knowledge Scale" before and after instruction. This scale measures a respondent's conception of the nature of scientific knowledge. In addition, intensive qualitative classroom observations were made in each of the classrooms between pre-and posttests. Subsequent analysis of classroom transcripts permitted both qualitative and quantitative comparisons between classrooms showing large changes in students' conceptions and those showing little change.

Results and Conclusions

Correlations between teachers' and students' Nature of Scientific Knowledge scores were low and did not support the contention that changes in students' conceptions of science are related to their teachers' conception of the nature of science. This result does not imply that a teacher is able to teach what he/she does not understand, but rather that beyond some essential level of knowledge or understanding a teacher's viewpoint is not significantly related to change in students' viewpoints. This reinforces the importance ofteacher behavior and classroom climate with respect to students outcomes. Indeed, it invites the question asked by the major portion of this research: What classroom variables are related to changes in students' conceptions of science?

We have called teachers/classrooms that showed large conceptual changes by students successful. We found that they had frequent inquiry-oriented questioning with little emphasis on rote memory/recall and seat work. Teachers in these classrooms were pleasant, supportive, and frequently used humor and anecdotes to promote instruction and establish a healthy rapport. As might be expected, successful classrooms were more often characterized by attentive students who were actively engaged with materials and subject matter. Explicit comments by teachers concerning the tentative, testable, and amoral aspects of scientific knowledge were common. Successful teachers/classrooms appeared to stress depth, breadth, and accuracy of content more often that the unsuccessful teachers/classrooms.

Implications for Science Education

The lack of a significant relationship between teachers' conceptions of science and changes in students' viewpoints clearly directs attention to the importance of a teacher's classroom behavior and the classroom atmosphere he/she establishes. Although teachers have been criticized in the past for failure to promote adequate student conceptions of science and are currently being rather strongly urged to do so, they have not been offered any useful advice on how to accomplish such an important goal.

An interesting issue is raised when one considers the current interplay between the "back to basics" and "scientific literacy" movements. Researchers have commented on the positive effects of drill and emphasis on lower-level understandings with respect to simple/concrete student understandings consistent with the intent of the "back to basics" movement. However, attention to drill and lower-level understandings were found in this study to be detrimental to students' conception of science, while stress on higher level understandings and inquiry were strongly associated with changes in students' conceptions of science. Since an adequate understanding of the nature of science is an attribute of the scientifically literate individuals the situation is ironic. The current educational atmosphere is placing stress on achieving both content outcomes and the more abstract "nature of science" outcomes, but it appears that different teaching techniques are needed for these outcomes. Since teachers are often evaluated on the basis of students' scores on achievement tests which predominantly measure lower-level knowledge, the plea for increased student scientific literacy may be asking for the accomplishment of the impossible!

It is clear that teachers who want to increase students' understanding of the nature of science and thus increase their scientific literacy must pay careful attention to what they say and do in the classroom and to the kind of classroom climate they establish. It is not enough for a teacher to have an adequate concept of the nature of science; he or she must communicate it to students.

by Norman Lederman, Professor of Science Education, Oregon State University, Corvallis, OR