The dynamic study of pendulum systems is considered an indispensable subject for physics and mechanics students in colleges and high schools. In this paper, a detailed methodology is given concerning the use of smartphones in pedagogical practical work for studying the dynamics of pendulum systems. Whereas, three aspects have been discussed…

At constant current (I) the forward bias potential (V) of a "pn" junction diode may be considered to vary linearly with temperature (t) within a temperature range. Based on this property we have constructed diode thermometer using germanium (Ge) and silicon (Si) diodes. The experimental "V-t" data at constant forward current…

With the benefits of low cost, energy efficiency, and environmental protection, photocatalytic hydrogen production is considered to be the most promising technology for the development of a clean and sustainable society. However, the utilization of photocatalytically generated hydrogen is not very common yet. Therefore, tertiary education urgently…

Electromagnetism is a complex topic for students at different educational levels. Perhaps one of the reasons for this is that students are unable to visualize the forces, fields, currents, and other electromagnetism key concepts that are related to the topic. Most teachers address this difficulty by including the use of some technological…

The Young's two-slits experiment is arguably one of the most famous and beautiful experiments in physics. In introductory physics labs the experiment is almost exclusively carried out using a laser, and it is introduced this way in some introductory physics textbooks. In the case of laser illumination, light passes directly through the slits and…

An experiment is described where a billiard ball and a golf ball were projected with backspin on a horizontal surface to measure the transition from sliding to rolling. During both phases, the torque on the ball is affected by an offset in the line of action of the normal reaction force.

The formation of chemical patterns is in general difficult to control due to the random diffusive motions of the reacting chemical species in solution. In this paper, we present a new method using audible sound to control the formation of chemical patterns obtained in blue bottle experiments. The waves generated on the surface of the solution by…

Electrochemistry represents a powerful sustainable method for chemical synthesis; however, its widespread application is limited due to the lack of exposure and appropriate basic training of synthetic chemists and engineers in electrochemistry and electrochemical engineering. The introduction of diverse laboratory practices to the current…

We investigated a very long chain falling from the pile on the edge of a table to the floor both experimentally and theoretically. In this very simple and novel configuration we showed that the velocity of the chain quickly converges to its asymptotic value, and that the steady-state velocity is proportional to the square root of the height of the…

The measurement of the charge-to-mass ratio, e/m, of the electron is a fundamental part of any study of electricity and magnetism. It is possible to use an apparatus designed to measure e/m for other things, including investigations of electron flow through a near vacuum, measuring a work function, and even exploring some quantum mechanics…

Our first experience of dimension typically comes in the intuitive Euclidean sense: a line is one dimensional, a plane is two dimensional, and a volume is three dimensional. However, following the work of Mandelbrot, systems with a fractional dimension, "fractals," now play an important role in science. The novelty of encountering…

In this paper, a simple method is described for visually demonstrating that the wavelength of light reduces when entering a medium of higher refractive index. When a violet laser (405 nm) is reflected off the surface of a Blu-ray disc (track spacing 320 nm) diffraction cannot occur since the wavelength is greater than the track spacing. However,…

Students determine the iron mass in dietary supplements using four colorimetric assays. These colorimetric assays were selective for Fe[superscript 3+]. It was complexed by thiocyanide, salicylate, gallic acid, and Fe(CN)[subscript 6][superscript 4-], forming blood-red, red, violet, and blue complexes, respectively. The [lambda][subscript max] of…

Applying the idea of green chemistry, we extended an esterification teaching experiment with isoamyl alcohol and acetic acid and reused isoamyl acetate in the transesterification reaction with KOH as the catalyst. As a result, isoamyl alcohol was produced and could be reused for the teaching experiment. The simplified experimental method achieved…

Benzoin, an [alpha]-hydroxy ketone, is stereoselectively reduced by sodium borohydride to yield hydrobenzoin, the stereochemistry of which is determined by acetalization and analysis of the derivative by NMR spectroscopy. This classical experiment has been enhanced by modern spectroscopic and computational analysis to enable students to…