Technical artifacts play a central role in teaching and learning about technology. The artifact exemplars used in the classroom to illustrate and discuss various technological concepts should therefore be carefully chosen in order to actually support the abstraction and successful transfer of these concepts. Research from the learning and cognitive sciences strongly suggests that this requires an understanding of how students actually perceive and conceptualize various technical artifacts, what similarities, differences and features are most salient and meaningful in their eyes. In this paper, we propose a grounded theory of how students differentiate and relate various complex technical artifacts. The core of our theory is formed by four hierarchically ordered juxtapositions: (1) technology versus non-technology, (2) everyday versus specialized, (3) private versus public, and (4) luxury versus necessity, which divide the realm of technical artifacts into five broad categories: high technology, household technology, public technology, real technology, and no/low technology. Our claim is that these differentiations and categories are generally salient and meaningful for students. Based on the theory of variation, we outline how they might help educators make more informed and systematic selections of exemplar artifacts to use in the classroom.