| This dissertation explores how students generate multiple external representations of their ideas about air, an "invisible" substance. External representations can serve a powerful role in placing students' ideas into the external world for reflection and abstraction. When provided the opportunity to represent their understandings of science in different ways, students generate increasingly coherent explanations of what they observe, including developing ideas about mechanisms that describe cause and effect. In this qualitative study, extended clinical interviews were conducted with twelve fifth-grade students from an urban public charter school. In study was designed to investigate students' ideas about air in the context of a linked-syringe device with the support of multiple representations. Students were given the opportunity to produce representations and to offer verbal explanations of the behavior of the syringes in a sequence of three interviews. In the first session, students were introduced to the linked-syringes, and they generated drawings to explain their thinking about air. In the second session, students created stop-motion animations of their explanations for air in the syringes. And in the final session, students built physical devices to demonstrate their ideas about air.;Careful analysis of each individual student's trajectory through the microgenetic design and a cross-student analysis reveal that the process of generating multiple representations facilitates how students think and reason about air. Drawings served to organize elements of the linked-syringe problem, providing students with focal points on which to direct their reasoning as they generated more precise explanations. Stop-motion animation supported students' efforts to make sense of processes that change over time, such as compressing the air inside the syringes. And, the construction of physical artifacts prompted students to think about air as a substance, as the activity allowed them to generate analogous physical models of the linked syringes. Furthermore, the students' productions provided the researcher with enhanced access to the substance of students' ideas as captured in their representations. The results of this study are presented in case-study form to highlight how representations serve as embodiments of the resources that students possess for making sense of science. This dissertation contributes to the resources perspective of the importance of external representations in students' development of coherent explanations of what they observe. |
