Teaching and communicating magnetism

This is a reprint of an article that I have written for the IEEE Magnetics Society Newsletter (November 2022 issue, edited by Jia Yan Law). Please do check out the Newsletter if you are interested in contents related to magnetism, technology, activities of the Magnetics Society as well as announcements of conferences, awards and events.

Nowadays, the majority of people are likely to encounter magnetism in their everyday lives, be it by simply seeing the magnets on their refrigerator door, using magnetized screwdrivers, navigating with a compass, swiping a credit card, undergoing an MRI scan, or saving an image file on their computer's magnetic hard drive. Of course, in the IEEE Magnetics Society, we have a much closer and more professional relationship with the world of magnetism, for instance, by conducting fundamental research or driving the evolution of magnetism-based technologies. This places us in an optimal situation to teaching and communication outreach in the field of magnetism!

It is not uncommon that very early on during their time in elementary school, students learn about the attraction and repulsion of bar-shaped magnets, usually in a playful way. Children learn that such magnets are usually divided into two sections, which are painted red and blue, representing the north and south poles, respectively. Different colors attract; the same colors repel. Sometimes, horseshoe magnets are occasionally introduced and shown to exhibit a particularly strong magnetic field between their poles. In any case, horseshoe magnets have clearly become the most widely recognized symbol for magnets and are often identified as such even by the youngest kids. 

At a later time, usually in secondary school, students are able to understand the origin and direction of magnetic fields. In particular, they learn about Oersted’s law and how electric current produces a magnetic field. Students, on the other hand, can understand how a time-varying magnetic field induces an electromotive force by studying Faraday’s law and electromagnetic induction. In addition, they also explore how magnetic fields influence the motion of charge, specifically via the Lorentz force, which is the fundamental cause of the Hall effect. In essence, the aforementioned topics constitute the basic education in magnetism that most people receive. 

Clearly, this basic magnetism education is lacking, and the subject would merit more attention, especially with regard to the vast number of magnetic-based applications in science and technology. Apart from that, it is worth considering about how to improve the presentation of magnetism in textbooks and the classroom. For instance, education researchers may object to the introduction of magnetic poles while claiming that this is only a model and magnetic charges do not exist. However, numerous studies have shown that simply mentioning common mistakes is not effective at all. Instead, the student's misconception persists. Another common misconception about magnetic fields is the belief that a magnet exerts a force on a static charge.

Rather than relying on the instructor to demonstrate the failure of the model, letting the students experience it themselves (e.g., through conducting experiments or numerical simulations) to resolve these problems. As well as this, cooperative learning can be more effective than traditional chalk talks and teacher demonstrations.

Misconceptions persist even at the university level. For instance, students often fail to identify the source of magnetic fields and tend to confuse magnetic force and field. We need to make it clear to students that electric fields are created by charges at rest, while magnetic fields occur due to charges in movement. In addition, many students believe that field lines are real. They need to comprehend that humans use imagination and simplification to describe complex natural phenomena. A final example is given by the confusion related to physical quantities, such as the magnetic flux density B and the magnetic field strength H, which are frequently both referred to as “magnetic field”. This ambiguity bewilders students, teachers, and even scientists in the field of magnetism. Here, people from physics, engineering, and other fields ought to come together and achieve consistency in the naming of magnetic quantities as well as their units. The IEEE Magnetics Society can take a leading role in this discussion. As a matter of fact, units can often help students understand the meaning of their respective physical quantities. 

All in all, we can further promote magnetism teaching and extend people's interest in magnetism! Taking appropriate steps to address misconceptions about magnetism is one step closer to an improved understanding. In addition, we could advocate for more timely magnetism content, such as magnetic recording and sensing technology, in the curriculum of high school science classes, which could help students understand the importance of magnetism early on in the curriculum. We are seeking articles the IEEE Magnetics Society Newsletter from inspired MagSoc members about teaching and communicating magnetism as an ongoing effort to reach out to students, instructors at different levels, and the general public. You can get in touch with me through mlonsky@physik.uni-frankfurt.de.