The central element of effective teaching is students' own (learning) activity. This, to a great extent, depends on teachers' instruction.
Therefore, it is important that teachers are able to perceive and manage students' activity. The purpose of this contribution is to portray the pre-service chemistry teachers' (N=24) initial competencies in observing (video) lesson and their ability to determine critical moments before entering a course focused on lesson observation.
The results show that teacher students focus more on a teacher (as an actor) than students or their activity, they also do not pay attention to subject content and are unable to find proper alternatives in case of so-called malfunctioning teaching. This shows the need to develop this teacher students' ability as opposed to contemporary focus on mere summaries of organizational forms and teaching methods.