How do science teachers perceive student engagement and its importance for teaching and what strategies do they use to create it? When 21 experienced science teachers in 4 focus groups discussed these questions, they brought up behavioural aspects, but also less visible emotional and cognitive aspects, as well as reciprocal aspects of teacher and student engagement. One teacher described engagement as 'the oil in the machinery' during lessons. Which role does the curricular content play? Well aware that some topics are seen as more directly interesting by students, teachers connect to these, but also use hooks, including lively demonstrations, role play and connections to the outside world. In this way, they aim to generate situational interest and engagement also in topics that are often viewed as less interesting, including atoms and molecules. These experienced teachers describe how they adapt their teaching to the group also in real time, based on the degree of engagement exhibited by the students. © 2023 The Author(s). Published by IOP Publishing Ltd.