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…

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…

The new 9-1 GCSE courses in Physics include reference to both permanent and induced magnets. In this article I briefly examine the origin of ferromagnetism, diamagnetism and paramagnetism and suggest a number of helpful classroom demonstrations.

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…

This is the second in a series of two articles on using antique devices to teach introductory physics. As mentioned in the first article, students can more clearly see the physics required for the operation of antique devices than for modern-day technological devices. This article further discusses antiques used to teach vibrations and waves,…

A quite simple and inexpensive technique is described here to represent the approximate shapes of atomic orbitals and the molecular orbitals formed by them following the principles of the linear combination of atomic orbitals (LCAO) method. Molecular orbitals of a few simple molecules can also be pictorially represented. Instructors can employ the…

Neo magnets are neodymium magnet beads that have been marketed as a desktop toy. We proposed using neo magnets as an alternative building block to traditional ball-and-stick models to construct carbon allotropes, such as fullerene and various nanocone structures. Due to the lack of predetermined physical connections, the versatility of carbon…

We use a tablet to experimentally determine the dependencies of the magnetic field (B) on the electrical current and the axial distance from a coil (z). Our data shows good precision on the inverse cubic dependence of the magnetic field on the axial distance, B?z[superscript -3]. We obtain the value of air permeability µ[subscript air] with good…

Previous research suggests that students; prior knowledge can interfere with how they observe and remember lecture demonstrations. We measured students' prior knowledge in introductory mechanics and electricity and magnetism at two large universities. Students were then asked to predict the outcome of lecture demonstrations. We compare…

The study investigated the impact on student motivation and understanding of magnetism of teaching sequences based on an inductive approach. The study was conducted in large lecture classes. A pre- and post-Conceptual Survey of Electricity and Magnetism was conducted with just fewer than 700 Thai undergraduate science students, before and after…

Employment of a data-acquisition system for data collection and calculations makes experiments with antennas more convenient and less time consuming. The determined directional patterns of the dipole antennas of different lengths are in reasonable agreement with theory. The enhancement of the signal by using a reflector is demonstrated, and a…

Demonstrations are a core part of science teaching. In 1980 a three-part assessment method using demonstrating was proposed. Known as DOE this consisted of demonstration, observation and explanation. DOE quickly evolved into POE: predict, observe, explain. In the light of experiences with POE and insights from constructivist theory we set out in…

An easy-to-see method for demonstrating and measuring the magnetic force between paramagnetic substance and a rare earth magnet is presented. The readily available trapezoid-shaped neodymium magnet and a low cost, easy-to-set-up, portable apparatus are used in the experiments.

A science toy sometimes called the "magnetic spinner" is an interesting class demonstration to illustrate the principles of magnetic levitation. It can also be used to demonstrate Faraday's law and a horizontally suspended physical pendulum. The levitated part contains two circular magnets encased in a plastic housing. Each magnet stays…