No abstract

This paper describes two studies comparing students’ explanations of an oxidation–reduction reaction after viewing the chemical demonstration and one of two different particulate-level computer animations. In the first study, the two animations differed primarily in the complexity of the visual images. Students viewing the more simplified animation provided more correct explanations regarding the identity of water and nitrate ions in the animations, the absence of ion pairs, the correct ratios of silver to nitrate ions and silver ions to copper atoms, the electron transfer process, size changes in the atoms and ions as the reaction occurred, the source of blue colour in solution, and the driving force for the reaction. Students viewing the more simplified animation also wrote more correct balanced chemical equations for the reaction compared to students viewing the more complex animation. Students in the first study also noted that the more simplified animation did not depict extraneous information (camera angle changes, the overabundance of water molecules), and did depict relevant information (atom and ion charges, the number of electrons transferred, the source of the blue colour). In the second study, the two animations differed only by whether water molecules were shown or omitted from the animation. Students’ explanations for most concepts were similar for these two groups of students; however, students viewing the animation with water molecules omitted were better able to identify nitrate ions in the animation. The only difference the students in the second study noticed between the two animations is the presence or absence of water molecules, but these student did not agree as to whether showing or omitting water molecules was more beneficial. The results of the two studies together suggest that showing or omitting water molecules in the animations had a limited effect on students’ explanations of the oxidation–reduction process.

No abstract

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