Fermat's principle states that a light ray refracted across different media will traverse the fastest path as the physics for Snell's law. A geometric proof of Fermat's principle will be demonstrated as an intuitive approach to learn high school geometry and physical optics. It will be proved explicitly by showing that all alternative paths need…

Huygens' principle in which every point on a propagating wave acts like a point source of radiation is a foundation principle of physics. Normally, Huygens' principle is demonstrated by passing a wave, for example a water or light wave through an aperture comparable in size to the wavelength. In this paper, an experiment is described in which a…

The peak position of the spectral density for blackbody radiation is given by the Wien displacement law. Within introductory physics materials it is often stated, or implied through example, that the color of the light emitted from a blackbody, such as the Sun, can be ascertained from knowledge of the position of that peak in the spectral density.…

Investigation of the kinetics of phosphorescence decay is a suitable learning task in studying the formal kinetics, and also properties of crystal phosphors. Kinetics of phosphorescence decay of crystal phosphors can be experimentally investigated at home as part of distance learning, using a conventional digital photo camera and a luminescent…

Light polarization, which is the direction of electromagnetic field oscillation, provides information that is highly different from that of spectral and intensity images and thus can enhance various fields of optical metrology. Polarization imaging can be also used by combining polarization and imaging, thereby providing polarization and spatial…

Nanoscience development affects almost every discipline of science, engineering, and technology. Not surprisingly, "the science of small" is also finding its way into science classrooms. In general, "nano" refers to a billionth of a meter--about 1/50,000 the width of a hair follicle. The term "nanoparticle" usually…

The Einstein-First project approaches the teaching of Einsteinian physics through the use of physical models and analogies. This paper presents an approach to the teaching of quantum physics which begins by emphasising the particle-nature of light through the use of toy projectiles to represent photons. This allows key concepts including the…

Science students should undertake engineering design projects and carry out scientific investigations, as recommended by the "Next Generation Science Standards" (NGSS Lead States 2013). However, studies show that students misconstrue the goals of science and engineering and are uncertain about their respective practices (Gilbert and Wade…

In the present article, the context-dependency of student reasoning is studied in a context of optics. We investigated introductory students' explanations about the behavior of light when different light sources, namely a small light bulb and a laser, were used in otherwise identical task assignments. The data was gathered with the aid of pretest…

The aim of this study was to determine the effect of inquiry-based laboratory activities on the students' understanding of the nature of science (NOS) in learning lights and optics topic. The method used in this research is quasi experiment. Sampling technique using random sampling to class and the samples were taken from grade 8 in one of junior…

Almost everyone "knows" that steam is visible. After all, one can see the cloud of white issuing from the spout of a boiling tea kettle. In reality, steam is the gaseous phase of water and is invisible. What you see is light scattered from the tiny droplets of water that are the result of the condensation of the steam as its temperature…

In a recent issue of "TPT," Gordon Gore made interesting observations about the red or yellow fluorescence when laser beams are passed through olive oil. With the excellent visuals contained in that article, we present a pictorial explanation of the questions that were raised in Ref 1 ("Fun with Fluorescence in Olive Oil,"…

We discuss how light acquired a velocity through history, from the ancient Greeks to the early modern era. Combining abstract debates, models of light, practical needs, planned research and chance, this history illustrates several key points that should be brought out in science education.

We repeated the historical infra-red radiation experiments performed by Melloni, to investigate why, at the end of his life, he came to the conclusion that radiation from light and heat rely on the same basic principle, what has been translated as the so called unitary formalism. In doing so, we profited from a Master thesis on heat radiation and…

A concept of the turbidimetric method for determining the concentration of ethanol in water-ethanol mixtures is described. A closed sample cell containing the analyte was heated to achieve vapor saturation and subsequent condensation. As the condensation occurred, the decrease in percentage transmittance with time due to light scattering was…