The aim of this study was to elicit students' conceptions about big bubbles in boiling liquids (water, ethanol and aqueous CuSO4 solution). The study is based on twenty-four students at different ages and grades. The clinical interviews technique was conducted to solicit students' conceptions and the interviews were analyzed to discover students' views. The interview findings established that students had difficulties with comprehending big bubbles in boiling liquids, especially in liquids other than water. Moreover, a few unexplored misconceptions about using different liquids were identified. The misconceptions may possibly stem from teachers and textbook authors, who have used water as an example in teaching about boiling. This suggests that we should use a range of liquids - not only water - when explaining boiling in curricular materials and during teaching.