A screenshot illustrating the introduction of the visualization of induction (see Fig. 3). Students are guided by the inquiry map to explore the visualization and to reflect on their observations by writing a note as shown in the foreground.
Description of the microscopic concepts and visualizations used in the three activities. The italics indicate the placement of the visualizations. The induction visualization occurs in the second activity.
Screenshots of the initial state and a later state of the visualization of induction. (The brackets and labels have been added for clarity.) The representation includes a static array of positive ions (circles filled with plus signs) that signify the nuclei and electrons minus a valence electron. It also includes the valence electrons (small circles filled with minus signs) that are free to move within the materials. The visualization of induction consists of a neutral material (at left, indicated by an equal number of positive ions and valence electrons) and a charged material (at right, indicated by an excess of valence electrons). These materials are separated by a gap represented by parallel vertical barriers to indicate that no transfer of particles is possible. When the simulation is run, the valence electrons move due to the net force they experience. As a result, the valence electrons at the right of the neutral material migrate from the negatively charged material to the left, resulting in a net positive side of the neutral material that is nearest to the negatively charged material.
Electrostatics pretest/post-test item and scoring guide. Example student responses are shown in italics.
Assessments of induction in the electrostatics project. Students responded to assessments before and after their interactions with the visualization of induction. Pre- and post-test responses were answered individually. The embedded responses (marked by ) were answered jointly by pairs of students collaborating on the project.
Pretest scores from all respondents were used to establish prior knowledge. To compare high and low prior knowledge, we divided the group at the median. To establish the group with minimal prior knowledge, we selected students whose highest score was no greater than an “incorrect or irrelevant” level of understanding (see Fig. 4) on the four open-ended items (total score less than 11).
Pre- and post-test performance on electrostatics. The graph on the left shows the overall gains for all participants. The graph on the right shows the gains for the groups formed by the median split on the pretest.
The trajectories of all students and students with the lowest prior knowledge for the five induction items given in Fig. 5. Note that the embedded assessments (EmA, EmB, and EmC, marked with ) were written by student pairs.
The verbatim responses and scores in parentheses of two students who started with minimal prior knowledge. Both students gave more sophisticated responses to the embedded items than on the pretest. After interacting with the visualizations, one of the students gave a response on the post-test that earned a higher score than on their pretest. Because responses to assessments embedded in the project are written by pairs of students, these students may have benefited from the support of a collaborator during instruction.
Article metrics loading...
Full text loading...