This study compares how the order of viewing two different computer animations affects students' particulate-level explanations of an oxidation-reduction reaction. The animations differ primarily in the complexity of the visual images used. The explanations from participants viewing the more simplified animation followed by the more complex animation were compared to those from participants viewing the animations in the opposite order using analysis of covariance, with participants' explanations prior to viewing either animation as the covariate. This comparison showed that those viewing the more complex animation followed by the more simplified animation provided better explanations than those viewing them in the opposite order. These concepts included the absence of ion pairs, the electron transfer process, size changes in the atoms and ions, the source of the blue color in solution, the fact that water was not forcing this reaction to occur, and writing a balanced chemical equation for this reaction. Participants had less difficulty interpreting the more simplified animation, in part because it showed the charges of the atoms and ions, the number of electrons transferred from copper to silver, the 2:1 reacting ratio of silver and copper, the size changes occurring as silver and copper reacted, and the solution becoming darker