Abstract
The processes of teacher professional development promote teachers' reflection in the context of pedagogical practice, and these need to be contrasted with the exercise in the classroom from the point of view of pedagogical knowledge of the content. This article aims to identify the elements of pedagogical knowledge of declarative content and in action of three chemistry teachers in the design, implementation and evaluation of practical work. From the declarative point of view, the appreciations and reflections were collected from the application of a semi-structured interview, and from the action point of view, the input was the episodes of practical work applied by the teachers participating in a lesson study program. From the transcription of the interviews and the videos of the practical work implemented, the elements of pedagogical knowledge of the content were identified. It was evident, from the declarative point of view, that the component with the highest frequency of relationships is the student's knowledge, and from the action point of view, the category with the greatest connections are the orientations towards teaching, in which the following of instructions, the difficulties of Learning and contrasting were the elements that promoted formative and summative evaluation. The teacher can develop activities to improve pedagogical practice and promote reflection processes based on the design, implementation and evaluation of practical work in chemistry.