In this experiment, students explore the synthesis and physical property characterization of the magnetic material strontium hexaferrite (SrFe[subscript 12]O[subscript 19]). SrFe[subscript 12]O[subscript 19] crystallites are prepared by a simple but fascinating sol-gel autocombustion synthesis. The prepared powder is compacted into pellets and…

Ampère's law is presented in introductory physics as a relation between the line integral of the magnetic field around a closed loop and the net current crossing any open surface spanning that loop. By allowing the surface to pass between the plates of a charging parallel-plate capacitor, Maxwell realized that this law is incomplete and introduced…

In one of the Faraday's experiments an electric current is induced in a conducting loop when a magnet in front of it moves towards or away from the loop. While the direction of circulation of the electric current in the loop has only two options, it depends on three experimental conditions that generate eight cases. Even though the Faraday law or…

In physics lessons at secondary school and experimental physics courses at universities, the magnetic field inside a current-carrying solenoid is considered quantitatively. The corresponding equations and theories are supported by measuring the magnetic flux density inside the solenoid with a Hall probe. It has already been shown that smartphones…

What colors do you use in class when teaching electromagnetism? For many physics educators we simply use what we learned or what is used in the textbook. Browsing through a large collection of introductory physics textbooks reveals that the vast majority use red for the electric field, blue for the magnetic field, and some shade of green for the…

AI offer first-hand account of a key stage in the development of parental choice in American public schooling, when Massachusetts state officials, concerned not to repeat the trauma and disruption resulting from mandatory reassignment of students to achieve desegregation in Boston, persuaded and helped more than a dozen other cities to adopt plans…

The directional feature of Earth's geomagnetic field has been contributing to the technological development and prosperity of humankind since the invention of the magnetic compass navigation centuries ago. Today, for instance, magnetoresistance sensors are commonly used in nanosatellites and unmanned aerial vehicles for high accuracy geomagnetic…

Many high school and first-year university courses include discussion of the magnetic effect of currents. Frequently discussed textbook examples include long, straight wires, circular current loops, and solenoids, partly because these examples are tractable mathematically. The solenoid naturally leads to discussion on magnetic materials since it…

A magnetic stirrer is an indispensable instrument in any laboratory setting. Commercially available stirrers are costly and have a defined life-span. The construction of a low-cost magnetic stirrer based on pulse width modulation is described. The design reported uses mainly recycled parts which results in a robust and efficient device at a very…

The magnetic field of Earth, B[subscript e], is an intriguing topic in the introductory physics curriculum that engages students' curiosity and inspires numerous speculations about the nature of this phenomenon. There are several methods for measuring Earth's magnetic field. Probably, the most widespread and visual method of measuring the field in…

In this work, an easy-to-set-up demonstration about electromagnetic induction is presented, where a simple toy electric motor is transformed into a musical instrument. With this creative way to mix physics and music, it is expected to engage and motivate students to learn about the basic concepts of electromagnetism.

Since its debut in Elihu Thomson's 1886 article "Novel Phenomena of Alternating Currents," the Thomson jumping ring apparatus has been a popular and captivating demonstration of magnetic induction. The components are quite simple. There is a solenoid, an iron core, and a ring. The demonstration usually begins with the professor saying…

The calculation of the magnetic field produced by a loop current using the Biot-Savart law is a very typical exercise in introductory university physics. However, the cases studied are limited, in most textbooks, only the circular arrangement is treated. In this article, we calculate the magnetic field of an elliptical loop current along an axis…

The distant magnetic field of a magnetic dipole is usually derived via the magnetic vector potential and substantial vector calculus. This paper presents an alternate proof that is less mathematically intensive, and that ties together various problem-solving tricks (the principle of virtual work, observation that only instantaneous quantities…

Resonance is an important, and rather dramatic, phenomenon in physics. The mechanical case of a mass-spring oscillator is generally the first example that students encounter in introductory courses. In electromagnetism, the resonance in driven RLC circuits is presented in analogy with mechanics, since the mathematical equations describing them are…