Recent reform initiatives in STEM disciplines inspired the development and implementation of integrated STEM approaches to science teaching and learning. Integrated STEM as an approach to science teaching and learning leverages engineering principles and practices to situate learning in an authentic and meaningful science learning environment. However, integrated STEM curricular activities can be cognitively challenging for learners, so it is essential that teachers employ scaffolding techniques to facilitate student understanding of the connections between concepts and practices of the integrated disciplines. In this paper, we describe Legitimation Code Theory as an analytical framework and provide an analysis of semantic patterns of an integrated STEM unit (written discourse) and a middle school teacher's enactment of that unit (oral discourse). Specifically, this analysis focused on the semantic gravity (SG), or level of context dependency, of the activities and dialogue present throughout the unit. Creating a semantic profile offers a snapshot of how abstract (weaker SG) or how specific (stronger SG) a concept is presented in relation to other concepts. Curriculum that presents ideas through the formation of semantic waves, or oscillations between areas of stronger and weaker semantic gravity, is linked to enhanced learning of complex ideas. The results of this study identify the areas in the curriculum unit and instruction that enable or constrain knowledge-building within the science classroom. We posit that the Legitimation Code Theory is a useful tool for developing and examining integrated STEM curriculum and its implementation.