Tangible Visualization as a Bridge for Barkhausen Effect
Presentation: Gerald Tembrevilla
Session E | 11:05 – 11:45 | Location: Room 1003
Demonstrating Barkhausen effect is a popular method used in physics classes to support the existence and fluctuations of magnetic domains in ferromagnetic materials. This demonstration, though attractive and extensively studied experimentally, may be less effective to high school physics students or even undergraduate students who will directly start to visualize the connection of the clicking sound to the invisible shifting of magnetic domains.
In order to increase the level of effectiveness of Barkhausen effect in visualizing the shifting of magnetic domains, 28 second – year Bachelor in Elementary Education students from a Japanese university were presented an improvised set-up of Barkhausen demonstration. The set-up introduced a crackling noise from both crumpled paper and plastic sheet. Then students’ pictorial representations of magnetic domains gathered through POE activity, drawings and diagrams, and answers to the questionnaires were analyzed based on the “modes of pictorial representations of magnetic phenomena” by Botzer & Reiner (2007).
Students’ pictorial representations were roughly categorized into three levels, sensory based, pure imagery and formalism based representations. A tally frequency result showed that students’ sensory – based representations are the highest. It may be related to the concrete nature of the activity. Pure imagery representation and formalism based representations came as the second and third highest, respectively.
These results showed that although even naïve students use imagery in physics reasoning, their imagery and corresponding pictorial representations evolve with time and context of interaction. Sensory – based representations are somewhat obvious and expected while pure imagery representations are interesting mixed of connections between sensory based and pure imagery itself. Interestingly, the improvised Barkhausen experiment provided a potential ‘bridge’ on the learning experiences of students from sensory based to pure imagery representations on the invisible movement of shifting magnetic domains in ferromagnetic materials.