A 2.7 m long stringless pendulum was set up to measure the coefficient of rolling friction of various balls, at higher rolling speeds than usually observed with a short stringless pendulum. The arrangement is easy to set up and makes an impressive classroom demonstration as well as an interesting laboratory experiment.

The notion of a boundary condition is typically considered to be somewhat advanced and not suitable to be introduced in high school level physics. In this article, we give a simple visual demonstration of the difference between Dirichlet and Neumann boundary conditions for a string which oscillates according to the one-dimensional wave equation.…

A hula hoop rotating around a person's waist is an example of circular motion where the centripetal force on the hoop is directed towards the centre of the circle rather than the centre of the hoop. The friction force on the hoop is relatively small by comparison since the hoop rolls around the waist. A slight complication is that the hoop rotates…

This paper takes a new look at a well-known physics demonstration--the Cartesian diver. A general overview is provided as well as some new twists on the old classic. A new version is proposed that can demonstrate some of the finer details of scuba diving. A hydrodynamic method of lifting sunken divers is presented.

Basic science courses, such as physics, are fundamental to precollege studies. For instance, in different engineering applications, electricity and magnetism require comprehending subjects such as electrical circuits and power electronics. However, abstract concepts such as electric or magnetic fields are often difficult to explain without visual…

Fermat's principle states that a light ray refracted across different media will traverse the fastest path as the physics for Snell's law. A geometric proof of Fermat's principle will be demonstrated as an intuitive approach to learn high school geometry and physical optics. It will be proved explicitly by showing that all alternative paths need…

Sound is an interesting topic for physics lessons at all ages. However, it is difficult to illustrate this ubiquitous phenomenon and many models do not adequately represent the properties of sound and thus promote unwanted conceptions. The experiment presented here avoids this by visualising sound itself with the help of the schlieren technique.…

Newton's cradle is often discussed in science classrooms as a clear example of the laws of conservation of momentum and energy although it has been shown that this use is somewhat misleading. Approaches to understanding the behaviour of this apparatus are often over-simplified and deficient or over-complex and with little impact among teachers. In…

Using Tracker, a popular video-based physics modeling tool, the position-time data of magnetically damped oscillations of a simple pendulum are acquired. Eddy currents are generated on an aluminum sheet as the magnetic pendulum bob passes over it and the induced magnetic field opposes that of the magnetic bob. This causes the damping. A…

Newton's cradle is a well-known physics toy that is commonly used by teachers to demonstrate conservation laws in mechanics. It can also be used to investigate the physics of colliding objects, by recording motion of the balls on video film. Various experiments are described using 3-ball and 5-ball cradles, showing how different types of collision…

Using smartphones in experimental physics teaching offers many advantages in terms of engagement, pedagogy and flexibility. But it presents drawbacks such as possibly endangering the device and also facing the heterogeneity of available sensors on different smartphones. We present a low-cost alternative that preserves the advantages of…

This paper presents a new way to demonstrate the principle behind mirages in air in the lab. The setup is simple and includes a modified laser illuminator that allows direct comparison between the deflected light rays and their straight path.

This paper presents the design and reports on the use of a simple and inexpensive cloud chamber kit that is compatible with active learning, experiential learning, and project-based learning strategies. The kit was developed for use in a first-year undergraduate nuclear science seminar class at a university in the US. Diffusion cloud chambers are…

A vacuum cleaner is used to isolate over twelve harmonics in a corrugated toy whistling tube. The toy tube is first taped along a horizontal surface. Then a vacuum cleaner with a hose diameter approximately the same as that for the toy tube is turned on. As the vacuum cleaner hose approaches one end of the corrugated tube, individual higher…

The transfer of electrical energy without any electric leads or cables is not only a modern subject of research, but the technology has already found its way into our daily lives. Especially in consumer electronics a lot of applications are commercially available, mostly non-contact charging applications for toothbrushes, mobile phones, etc. On…