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…

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…

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…

In this experiment we have first determined the focal length of an equiconvex lens. We have observed that a real image can be formed by the lens on the same side of the source if the source is sufficiently strong. This is due to the reflection from the concave surface of the lens. We have measured these image distances for different object…

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…

The refractive index (RI) is probably the single most important parameter in optical systems. Chromatic dispersion, on the other hand, indicates how the RI depends on the wavelength and is central in, e.g., optical communication systems. Chromatic dispersion also plays an important role when teaching optics due to the captivating natural…

The wave nature of light has been widely demonstrated in a double-slit experiment, which has played a special role in physics teaching. When monochromatic light passes through the double-slit sheet, the diffraction and interference fringes can be observed in the far-field regime. The interference of light causes the beams passing through the two…

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,…

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…

On April 14, 1912, the British passenger liner R.M.S. "Titanic" struck an iceberg. The ship sank in a fraction of the time designers had estimated following a worst case scenario. The purpose of this article is to examine the atmospheric refractive phenomena that might have played a significant role in obscuring the iceberg from…

The interference pattern between two harmonic oscillations with slightly different frequencies are called beats. The beats, as a combined motion, have two different periods, one approximately equal to the period of the original oscillations, and another that is significantly longer and is related to the variable amplitude of the motion. The main…

The overhead projector is perhaps passing out of use, but it is still a useful device with which to do lecture demonstrations. In my early years at Kenyon I was teaching the pre-med course, and found that the overhead projector was an ideal platform for showing the phenomena of polarized light. This note is a discussion of how I learned to use the…

The Crookes radiometer (also known as a light mill) is a fascinating sunlight-powered device, in which a set of vanes is placed inside a glass bulb within which a partial vacuum has been pulled. The vanes then rotate when sunlight shines on the bulb. The reason for the turning of the vanes was subject to intense debate and many students still have…