Diffraction refers to a kind of optical phenomena which occurs when light approaches an element (object or aperture) whose features are in the range of the illuminating wavelength (small apertures, sharp edges). It can be explained by means of the undulatory nature of light or also geometrically by using simple ray optics. Diffraction phenomena…

The trajectory of a ball rolling across an inclined plane was recorded on video film to determine if it followed a parabolic path as others have suggested. The challenges in this case were (a) to determine the magnitude and direction of the friction force on the ball, (b) to determine the effect of the friction force on the trajectory and (c) to…

We propose an experiment in which the sound of a drumroll is recorded and analysed according to a simple mechanical model in which the inelastic restitution coefficient of the collision between the stick and drum surface, as well as the ongoing kinematics of the drumstick, are considered. The agreement shows that this model is well suited for…

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.…

The Widlar current source is one of the basic current sources that undergraduate students encounter throughout their learning process on electronics courses. The Widlar current is actually given in terms of a transcendental equation. Although an analytical solution exists in terms of the Lambert W function it might not be that useful for students…

Astronomy is one of the few sciences where the data (star-light) can be seen by all. Yet, there is a disconnect between a typical undergraduate lecture and, for example, where a planet may be in the sky and how to observe it. With the advent of moderate cost, high-quality 'back-garden' astronomy, and standard computers powerful enough to produce…

In this article we present a simple experimental set-up to determine the band gap of germanium and silicon using the "ExpEYES-17" kit. The experiment is based on the temperature dependence of the reverse current through germanium and silicon diodes at different temperatures. The experimental values are found to agree well with accepted…

Undergraduate physics laboratory exercises are very important in shaping students' attitude to science, especially for future teachers. Recently, it is necessary to look for ways to easily create large quantities of experimental sets, not only for institutional use, but also for sets that can be produced in large quantities and distributed for use…

The necessity to teach experimental physics in the pandemic period motivated the development of practices in which students may take measurements with instruments constructed by themselves. In this article, we present an experimental practice to approach Newton's law of cooling with a thermoscope (the earliest device for detecting changes in…

In this article we present a simple technique for determination of the Young modulus of the material of a metallic ruler using it as a cantilever. This method employs with a slide potentiometer and a digital multimeter. The linear region of potentiometer resistance which is calibrated in terms of length has been used to record the load vs.…

We have investigated the motion of water flow through glass tubes of different shapes by calculating the value of the Reynolds number denoted as Re. We know that at a given flow rate the value of Re determines the type of flow being classified as laminar, transitional or tubulent. The dependence of Re in different configurations of glass tubes as…

The static equilibrium properties of a spool, resting on an incline and subject to the tension exerted by a string wrapped around the core cylinder, are studied by means of Newtonian mechanics. The overall behaviour of this system is imagined to be similar to that of a doggie kept on a leash. Starting from the well-known mechanical properties of…

During the COVID-19 pandemic and subsequent lockdown, both schools and universities faced significant challenges in moving teaching from an in-situ setting to a remote one, this included laboratory experiments. This paper presents an experiment developed to use a phone's in built pressure sensor, common to most smart phones. By using this sensor…

The falling rod paradox, i.e. the fact that the tip of an almost horizontal rod falls with an acceleration 'higher than g', when the other end is hinged or supported, is a popular physics demonstration. It can be visualized by placing e.g. a coin on the tip of the rod and fixing a cup next to the coin. When the rod is released the free-falling…

A practical experiment is described to estimate the distance to a star using simple equipment, suitable for secondary or undergraduate students. The brightness of the star is visually matched to a miniature filament lamp, and its distance inferred from the inverse square law. Students gain an appreciation of astronomical units and practice in…