We describe a new approach to the use of video-based technology for conducting controlled experiments in classroom contexts. Specifically, we describe a process for editing video recordings of live classroom lessons to create multiple versions, such that only one aspect of the lesson is systematically varied. Other aspects of the instruction are…

A critical incident is a situation or event that holds significance for learning, both for the students and teachers. This paper presents four examples of critical incidents from a Year 7 teacher's lesson excerpts in Indonesia involving teaching of fractions, to show how they shaped classroom situation, brought forward elements of conflict, and…