A study of future physics teachers’ knowledge for teaching: A case of a decibel sound level scale

Abstract

This study examines the knowledge for teaching of prospective secondary physics teachers as related to the subject of sound waves, specifically the topics of sound level and sound intensity. The data is comprised from future teachers’ responses to the task in which they had to compose a script for an imaginary dialogue between a teacher and a group of students and provide a commentary elaborating on their instructional choices. The topics selected for the task were chosen intentionally as they provide authentic and rich opportunities to bridge mathematics and science concepts while challenging future teachers to consider logarithmic measurement scale and its role in science. The task provided the beginning of the dialogue, that featured a student’s confusion related to the measurement of the sound level using a decibel scale. Future physics teachers were asked to extend this dialogue through describing envisioned instructional interactions that could have ensued. The instructional interchange related to the relationship between sound intensity and sound level, and particular teachers’ responses to the student ideas related to the meaning of a decibel sound level scale were categorized as featuring superficial or deep, conceptual or procedural knowledge for teaching. We describe each category using illustrative excerpts from the participants’ scripts. We conclude with highlighting the affordances of scriptwriting for teachers, teacher educators, and researchers.