This article reports on a study of teachers' views on the motivational value of practical work. The findings suggest that what teachers frequently refer to as motivation is, in a psychological sense, better understood in terms of situational interest. The fact that situational interest is unlikely to endure beyond the end of a lesson helps to explain why students need to be continually re-stimulated by the frequent use of practical work. The implication is that simply doing more of the same practical work is unlikely to motivate students towards opting to study science in the post-compulsory phase of education.