Situational interest is a relatively transient reaction to highly stimulating factors in the immediate environment, whereas individual interest is a relatively long-term preference for a particular subject or activity. It has been proposed that regular experiences of situational interest in a subject may eventually lead to the development of individual interest in that subject. Importantly, this should also result in an increase in behaviours related to that domain. For example, a student who develops an individual interest in science would be expected to spend more time on science-related activities such as reading about science, talking with other people about science, or watching science shows on TV. However, the extent to which this does happen has not yet been established. The purposes of this study were to find out whether regular experiences of situational interest in science classes can enhance individual interest in science and whether there is an associated increase in science-related activities. The participants were primary teacher education students who were enrolled in a semester-length science course. Data were collected using a survey, an interest inventory, open-ended questionnaires and interviews. It was found that regular experiences of situational interest during the course were associated with positive changes in individual interest in science and increased participation in science-related activities. These changes remained relatively stable over a delay period of 10 months after the end of the course.