This theoretical article problematizes the access to disciplinary knowledge that different physics representations have the possibility to provide; that is, their disciplinary affordances. It is argued that historically such access has become increasingly constrained for students as physics representations have been rationalized over time. Thus, the case is made that such rationalized representations, while powerful for communication from a disciplinary point of view, manifest as learning challenges for students. The proposal is illustrated using a vignette from a student discussion in the physics laboratory about circuit connections for an experimental investigation of the charging and discharging of a capacitor. It is concluded that in order for students to come to appreciate the disciplinary affordances of representations, more attention needs to be paid to their "unpacking." Building on this conclusion, two questions are proposed that teachers can ask themselves in order to begin to unpack the representations that they use in their teaching. The paper ends by proposing directions for future research in this area.