With the wide availability of strong neodymium magnets, the slow and stately fall of a magnet through a conducting pipe has become a favorite classroom demo for teaching electromagnetic induction, Newton's third law, and Lenz's law. Since Lenz's law is conceptually difficult for some students, several authors have used this demo to explore in…

Measuring magnetic induction is occasionally performed by our students during their academic training in physics. Among the various methods used to measure it, the Hall effect is the most common and widespread. Another way consists of employing an electronic flux-meter. It is constituted by a small flat coil (SFC) connected to the input of an…

It can readily be demonstrated that when a low frequency alternating voltage is applied to an iron-core coil the impedance is much higher than the direct current resistance of the coil. To understand how the high level of impedance arises it is necessary to explain how magnetic and electrical induction give rise to a current in the coil that…

[This paper is part of the Focused Collection in Artificial Intelligence Tools in Physics Teaching and Physics Education Research.] Artificial intelligence-based chatbots are increasingly influencing physics education because of their ability to interpret and respond to textual and visual inputs. This study evaluates the performance of two large…

The classic demonstration illustrating Lenz's law by dropping a magnet through a copper pipe is presented using household aluminum foil right out of the box. Then comes the surprise. The teacher presents an aluminum foil cylinder with a missing lengthwise slice (cut before class). Will the demonstration still work? Students are amazed at the…

This paper describes a pictorial approach to Lenz's law that involves following four steps and drawing three pictures to determine the direction of the current induced by a changing magnetic flux. Lenz's law accompanies Faraday's law, stating that, for a closed conducting loop, the induced emf (electromotive force) created by a changing magnetic…

In this article, we outline a demonstration that is relatively simple to perform but whose results require a quite subtle interpretation of Faraday's Law. When a very small magnet is dropped through a coil it can tumble as it falls leading to 'spikes' in the measured emf signal. The experiment, and demonstration, can be used in an introductory…

Light polarization, which is the direction of electromagnetic field oscillation, provides information that is highly different from that of spectral and intensity images and thus can enhance various fields of optical metrology. Polarization imaging can be also used by combining polarization and imaging, thereby providing polarization and spatial…

Here we present an inexpensive proposal to experimentally study Faraday's law of induction. The experiment uses low-cost materials, a computer with a sound card and a smartphone, both running free software. A value proportional to the induced electromotive force is measured with the computer's sound card and the data related to the magnetic field…

Magnetism and its various applications are essential for our daily life and for many technological developments. The term "magnetism" is almost always used as a synonym for ferromagnetism. However, the magnetic properties of the elements of the periodic table indicate that the vast majority of elements are not ferromagnetic, but rather,…

Recent GCSE and IGCSE specifications include reference to both permanent and induced magnetism, giving the opportunity for novel classroom demonstrations based on ferromagnetism and paramagnetism, and the transition between these phases. Ferromagnetic materials lose their magnetism if raised above their Curie Temperature, a specific temperature…

The answer to this month's question, "Can electromagnetic waves affect emotions," is yes. Wherever there are electromagnetic (EM) waves (basically everywhere!), there is the potential for them directly or indirectly to affect the emotions. But what about the likely motivation behind the originally-posed question? Can EM waves affect your…

In electromagnetism, to determine the direction of the electromagnetic force and magnetic field, the right-hand rule (RHR) is used. Previous researches show that students have difficulty in applying the RHR. This research is aimed to find out the factors which make it difficult for the students to apply the RHR. To achieve this, qualitative case…

The concept of reactance in AC electrical circuits is often non-intuitive and difficult for students to grasp. In order to address this lack of conceptual understanding, classroom exercises compare the predicted resistance of a power tool, based on electrical specifications, to measured resistance. Once students discover that measured resistance…

Promoting facility with content knowledge is one of the most important objectives of science teaching. Conventionally, the focus for this objective is placed on the substantive side of content knowledge (e.g. science concepts/laws), whereas its epistemic or ontological aspects (e.g. why do we construct concepts?) rarely receive explicit attention.…