Designing and evaluating experiments based on electromagnetic induction to support general physics

Abstract

In this paper, based on the phenomenon of electromagnetic induction and Lenz's law, we have designed a model of a falling magnet through various types of tubes, including plastic tubes, aluminum tubes, solid copper tubes, and slit copper tubes. Results of the analysis show that non-conductive tubes (plastic) do not affect the free fall of the magnet. Metallic tubes (aluminum, copper) create a relatively large resistance force against the falling magnet, resulting in a significant reduction in the magnet's average falling speed. Specifically, the average falling speed of the magnet in the copper tube decreased by nearly 16 times compared to that in the plastic tube, and decreased by about 9 times when using the aluminum tube. The falling time in the slit copper tube is also nearly identical to that in the solid copper  tube, indicating that eddy currents induced in the metallic tube not only circulate in a circular pattern along the radial
direction but can also swirl in various other directions on the tube's surface. The results also show that the falling speed of the magnet in the metallic tube quickly reaches a constant value within a short period of time.