This paper reports on two experiments in mapping the affordances of mobile devices in supporting teaching and learning. The first argues for personally imagined rather than fixed affordances of educational technologies--what a technology "affords" is not static but is rather how an individual imagines a technology's use and how this is enacted. The second melds affordance theory with the structure of realist evaluation and positions affordances as mechanisms in selected educational settings. The paper's findings are drawn from observation and a review of literature. [Note: The publication year (2019) shown on the full text is incorrect. The correct publication year for v5 n1 is 2018.]