This study offers a systematic analysis of uncertainty in communication education by examining communication goals and challenges in the context of collaborative creative problem-solving in engineering assignments. Engineering design projects are seen as having the potential to help K-12 students learn to deal with uncertainty as well as a means through which to learn science and math. Educational researchers have emphasized the cognitive or very general social aspects of this context. The current investigation argues that collaborative, creative design work involves a distinctive constellation of communication challenges: ongoing efforts to temporarily suspend normal inclinations to understand well, to appraise what we understand, and to do so in relation to instrumental, identity, and relational meanings. This argument guides textual analyses of transcripts of fifth-graders assigned to groups tasked with designing and building an environmentally beneficial robot. Implications for communication education are discussed. (Contains 3 tables.)