The aim of the work presented here was to devise an activity associated with factors affecting boiling points. The intervention used a four-step constructivist-based teaching strategy, which was subsequently evaluated by a cohort of students. Data collection consisted of application of a purpose designed questionnaire consisting of four open-ended questions administered to 48 pre-service science teachers enrolled in the science education department in the faculty of education at Giresun University, Turkey. The research findings suggest that this four-step constructivist teaching helps pre-service science teachers shift from alternative conceptions towards ideas more in accord with scientific ones, suggesting the activity and teaching is an effective way in refuting and overcoming their alternative conceptions. The use of a delayed test to evaluate student understanding suggests that the teaching approach used helped students to retain the scientific conception in their long-term memory. (Contains 2 figures and 3 tables.)