What a Metal Pipe Can Teach You About Magnetism

Abstract

Magnets are familiar objects and yet magnetism as a concept remains challenging. A casual search of YouTube for magnets reveals a staggering number of videos, interesting demos involving electric and permanent magnets, and entire channels devoted to various uses for magnets. It is far more difficult to find descriptions that can help students think quantitatively about magnets. The underlying quantum theory of magnetism is usually difficult for students, and even the more vector fields-based classical approach can prove to be challenging. The task, in our opinion, is made easier by learning through experimentation, specifically by exploiting the dipole model of a magnet and using the concept of a magnetic moment to characterize single magnets and magnet assemblies by joining single discs. This work is guided by the idea that a simple experimental setup and a familiar theoretical framework can greatly aid in learning a new concept. In this article we hope to contribute to a growing list of simple experiments suited to a sophomore- or junior-level course in electromagnetism.