The photoelectric effect consists of electrons emerging from the region near the inner surface of a metallic solid toward the outside vacuum, when the metal surface is illuminated. The effect depends on the frequency of the light waves and the properties of the metal surface. In particular, a minimum or "threshold" frequency of light is…

The falling temperature of the photosphere with height is responsible for the effect known as limb darkening. The Sun is not equally bright all over the disc. When we observe the Sun towards the limbs, it appears to get darker. Light from the photosphere travels through an absorptive medium. Therefore, one can see only so far into the photosphere.…

Students are well aware that when an electric current flows through a light bulb, it glows. As their grade increases, they have understood that electric current flows because electric charges move. Since the transfer of electric charges is not visible, students have many cognitive difficulties in understanding this process, and teaching materials…

Solar limb darkening is a prominent feature seen in white images of the Sun: the brightness of the solar disk is greatest at the solar center and decreases radially outward towards the limb. White light images can be used to examine and even model limb darkening; however, the limb-darkening effect is, in fact, wavelength dependent. Limb darkening…

The hydrogen spectrum is one of the most commonly demonstrated and most commonly studied. After the visible spectral lines (Balmer series) are explained by the Rydberg's formula, it becomes immediately apparent that there will also be similar infrared and ultraviolet series. As you may have taught your students, these are called the Paschen and…

In this paper, we propose a simple yet generic and versatile method to measure the position of a moving body as a function of time. Apart from very basic equipment such as carts and wheels, only a laser pointer or a similar device and a smartphone are necessary. By attaching a source of light to a cart and video filming its movement on a…

This paper presents an innovative teaching approach that integrates photoelectric technology with analytical chemistry instruction through inquiry-based learning (IBL), using cerium as a selected analyte. With the advancement of science and technology, a strong foundation of basic knowledge and methodologies is crucial in analytical chemistry…

Most people are familiar with arc discharges through the use of simple gas lighters within the home but corona discharges are not so common. This note presents students with three simple corona discharge experiments so that they can appreciate this form of electrical discharge. Firstly, one detects whether positive or negative ions are created;…

Light emitting diodes have been used to determine Planck's constant in introductory physics laboratories. One common method relies on the energy of the light emitted by the LED and its relation to the energy gap in the solid of which the diode is composed. However, there could be a problem with the data that are collected for this experiment. For…

Due to social distancing constraints during the COVID-19 pandemic, several experiments were designed in the Fall 2020 and Spring 2021 semesters in our Electrochemistry and Corrosion elective course to demonstrate electrochemical phenomena and applications at the students' homes with a kit sent by the school. We report here a student-designed…

It is well known that when two waves are added they produce beats. These beats are the amplitude modulation of the initial waves and occur periodically at a rate equal to the frequency difference of the two waves. Acoustical beats arise from sound waves of nearly equal frequencies. Optical beats arise from the interference of two light waves of…

This work presents a sequence to introduce resistive gas sensors in the classroom. It explains the physical principle of the metal oxide semiconductor sensors and exemplifies its real interfacing through the sensor model MQ-2. Besides, it also presents the design of two electronic systems to indicate the level of alcohol concentration in the air,…

We calculate the frequency of matter-wave of electrons orbiting the hydrogen nucleus at the ground state. It is the same as the value of light frequency corresponding to the ground state from the Rydberg's formula. The result will stimulate students' interest to further understand the mechanisms of quantum theory.

An experiment for the calculation of the degree of double bond conversion, after a polymerization reaction, of photopolymerizable liquid monomers using FTIR-ATR spectroscopy is reported. The experiment was successfully conducted with undergraduate students in materials engineering during the Fundamentals of Polymeric Material course. Students…

The topic of atomic spectra is part of university and secondary school curricula around the world. Relatively little research, however, has been done on the learning and teaching of this subject, despite the fact that it forms a foundation for advanced study in quantum mechanics, astronomy, and astrophysics. A systematic investigation into student…