Enabling students to recognize and evaluate the ubiquitous impact of computing technology on society is an internationally proclaimed goal of a K-12 computing education. To that end, students need to actually engage with their computing knowledge in concrete everyday situations. From the perspectives of learning transfer and variation theory, we conducted three iterations of a classroom intervention and qualitatively analyzed students' learning processes. As a result, we propose a model of four so-called critical aspects of everyday computing technology in that context. We present various classroom situations and learning experiences in relation to those aspects, and discuss what seems to have enabled or prevented meaningful learning. In particular, we found that several students had difficulties in conceiving of computing technology as simultaneously economical and powerful, thus limiting its potential ubiquity. We discuss our findings in the context of contemporary theories of learning transfer and argue that they suggest specific issues that may seriously inhibit students to appropriately engage with their computing knowledge in the context of everyday technologies.