Fostering Diagrammatic Reasoning in Science Education

In a study with 56 third-graders, we tested whether reasoning with line graphs can be enhanced by representational activities within a curriculum on floating and sinking of objects in water. We hypothesized that representing mass and volume on the opposite arms of a balance beam allows the simultaneous consideration of both dimensions for a representation of density, and therefore will be particularly helpful for drawing inferences from the slopes of line graphs. In an experimental classrooms study, half of the students used the balance beam, while the other half worked with self-constructed representations. Five months after the instructional unit, students who had been familiarized with the quantitative interpretation of proportional information on the balance beam outperformed students who had worked with self-constructed representation in their interpretation of line graphs referring to density, but only marginally when referring to speed.