This article summarizes an investigation into how Flash-based cartoon video tutorials featuring molecular visualizations affect students' mental models of acetic acid and hydrochloric acid solutions and how the acids respond when tested for electrical conductance. Variation theory served as the theoretical framework for examining how students compared and contrasted their understanding of weak and strong acids to the tutorials. Specifically, students' ability to recognize variation between their mental models and the events portrayed in the videos was examined through picture construction exercises and semistructured interview questions focused on metacognitive monitoring. Interestingly, the items noticed as being in variance were items that were emphasized by still image representation in the tutorials prior to showing the visualizations. Mechanistic items, specifically movement of ionic species toward electrodes, were replicated in students' drawings only if they were explicitly conveyed, but students were not inclined to mention them as features in variance with their initial understanding. Overall, scaffolding animations in a cartoon context with explicit connections between experimental evidence and the submicroscopic level resulted in students being proficient at replicating what they explicitly observed both structurally and mechanistically.