Too often, science courses (e.g, biology, chemistry, and physics) are disconnected from one another. When this happens, students often don’t see how the different disciplines relate to one another. For example, we have heard students ask, “Which is bigger, a cell or an atom?” Indeed, when students are asked about cells and molecules, they often get them mixed up or think that “molecules” are just things learned in chemistry (Driver et al., 2014). Through Science and Engineering Practices (SEPs) and Crosscutting Concepts (CCCs), the NGSS has encouraged integration across disciplines (Czerniak & Johnson, 2014). While much progress has been made in helping students make cross-disciplinary and interdisciplinary connections with SEPs and CCCs, disciplinary core ideas (DCIs) are still often siloed. One way to help students see connections between disciplines is to find DCIs that can be connected across courses. In this article, we demonstrate how we used a lesson on the concentration and temperature of reactions (HS-PS1-5) to make connections to the digestive system and cellular respiration (HS-LS1-7)