Background: We examine the development of youth sociopolitical consciousness and agency in an eighth-grade science classroom as students of color engage in critical speculative design activities, exploring the multi-scalar, racial realities and possibilities of the science and engineering of pervasive digital technologies--specifically involving the entanglement of lightwaves and melanin in computer vision and artificial intelligence (AI) technologies. Methods: Through case studies of two girls of color (ES and GS), we analyze the youths' learning pathways across three instructional phases: threading practices (learners' sociopolitical interpretation); weaving practices (learners' coordination of multiple ways of knowing and being in relation to their interpretation); and patternmaking practices (learners' visions of more just patterns, practices, and politics through speculative design). Findings: Our analyses show how youth use their felt, cultural, and community knowledges, as well as their developing scientific knowledge of physics, to confront and analyze manifestations of racial bias in technologies. The findings highlight the significance of teachers' pedagogical support and providing opportunities for meaningful transdisciplinary science investigations and speculative designing for more just and thriving futures. Contribution: The Critical Speculative Design Pedagogy framework developed suggests how such activities in the classroom can cultivate equitable, expansive science learning that is consequential to youth and their communities.