Concepts relating to enzymes and energy are central to understanding chemical and biological processes at the molecular level. Student learning of these crosscutting concepts can be challenging, so it is important to identify misconceptions and remediate them early, especially in introductory classes. Here we describe an activity in which undergraduate introductory biology students timed themselves crushing pieces of cereal to simulate and quantify the progress of an enzymatic reaction in the presence of competitive and noncompetitive inhibitors, and we asked students to connect the cereal analogy to concepts of thermodynamics. We developed an assessment and short surveys to evaluate the impact of the activity and to identify persistent misconceptions. Measurable improvements of assessment scores and qualitative student survey responses demonstrate the value of including a hands-on activity along with other modes of instruction.