Their consideration is also important in order to prevent traditional teaching resources from becoming ‘traps’, such as those graphs, illustrations and texts that could reinforce prior ideas that are not scientifically acceptable (Leite and Afonso 2001; Linder 1993; Wittmann et al. 2003). Science fiction films are another popular ‘trap’ as a possible source of misconceptions (Barnett et al. 2006). Furthermore, when using analogies, such as using water waves to explain sound waves, one must bear in mind the considerable limitations and potential ‘traps’ thereof, despite the proven scientific and didactic value of analogies (Podolefsky and Finkelstein 2006, 2007). They will be productive only when used as ‘bridging analogies’. To this end, instructors must choose a bridging strategy that builds on students’