A laboratory experiment has been designed for teaching laboratories aimed at training students in the basics of spectroscopy in junior and senior level undergraduate chemistry courses. Despite the ubiquity of light-based tools in modern science, students often find it difficult to comprehend light and light-matter interactions. A portable…

From my home on the west bank of the Columbia River in Richland, Washington (46.3°N latitude), I have an unobstructed view of the sunrise along the east bank during an entire year. As a retirement project after a career of teaching and research in physics, I decided to take photographs of the sunrise for a year and, and at the same time, carry out…

Colloidal stability is one of the most important criteria in the application strategy of colloidal nanoparticles in the continuous phase. The branches include ecology, involving coagulation as a purification method; medicine as nanocarriers; biology as blood coagulation, etc. A chemist versed in these concepts is a high-performing chemist in…

The camera obscura is a well-known optical device in the form of a closed box with a hole in one of its walls through which light rays pass, forming an inverted image of the external objects on the opposite wall, as can be seen in Fig. 1(a). Despite the simplicity of its basic design, they have been widely used by scientists and artists. In…

There are several 'cool' mechanisms that result in materials luminescing or emitting light. Artificial luminescence has often been created by mimicking nature and there are many examples of applications in society. It is very likely that most of your students will have observed luminescence in one form or another, such as glow sticks,…

Gravity bends light. One can argue this by reasoning that a beam of light should travel in a curved path when viewed from within an accelerating frame of reference, and then invoking Einstein's principle of equivalence, which asserts that the effects observed in an accelerating frame of reference are indistinguishable from the effects observed in…

We demonstrated that an optimally designed pinhole camera can be used as an astronomical tool to observe the libration and apparent diameter change of the Moon at night. The libration and apparent diameter change of the Moon were observed using a handmade pinhole camera with a diameter of 0.65 mm and a focal length of 400 mm. It was found that the…

Photochemical reactions are the reactions that are induced by light. Many of these reactions are found in natural processes, including photosynthesis and the formation and decomposition of ozone in the atmosphere. Classroom demonstrations are effective in enhancing students' learning and retention. Herein, we have developed a simple demonstration…

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…

Nearly everyone, including physics students, finds rainbows to be fascinating and much has been written about them. For example, in a 2020 paper, Kenneth Ford sets forth the basic theory of rainbows created by water droplets at the level of geometric optics and uses a graphical approach to address the question of the relative intensities of the…

In introductory texts, some "special" rays are selected to draw the image produced by lenses and mirrors. After teaching special rays, students usually ask how to draw an arbitrary ray. One method for drawing an arbitrary ray is the "tilted principal axis." As an example, the tracing of an arbitrary ray in diverging lens is…

In this paper, an experimental setup composed of a color-mixing device, power supply, and spectrometer is developed. This setup is available for students to do hands-on color mixing with red, green, and blue light in undergraduate labs. LED volt-ampere and spectrum characteristics are investigated. The apparatus was used to perform additive color…

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…

This experiment demonstrates that copper(II) chloride dihydrate (CuCl[subscript 2]·2H[subscript 2]O) in different solvents (acetone, isopropyl alcohol, or water) displays divergent colors and visible-near IR spectra. Both the reactions of these solutions with 2 equiv of sodium hydroxide (NaOH) and the direct solid-state reaction of CuCl[subscript…

The refractive index is a number that governs how light changes its direction of propagation as it enters one material medium from another. This phenomenon is known as refraction and the angles of incidence and refraction of light, referred to the normal to the interface of the two media at the point of incidence, are related by Snell's law. The…