The "Golden Penny" demonstration is a popular experiment that involves treating copper coins with chemical reagents to form brass, an alloy of copper and zinc that has a golden color. Reported here is a very simple modification for forming golden color on copper coins that does not require the use of chemical reagents. Instead, golden…

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,…

Plant leaves are green because they contain the green photosynthetic pigments, chlorophylls a and b. Popular science literature, and sometimes even textbooks, state that the greenness is caused by reflection of green light by chlorophyll. In the present study, we compared the reflectance spectra of green leaves to yellow or white leaves of the…

Chladni patterns are one of the most fascinating physics demonstrations. They can be produced very easily using commercially available apparatus based on metallic plates attached to a mechanical driver, similar to a loudspeaker without the membrane, and a signal generator. The figures are observed using sand sprinkled on the surface of the plate.…

So-called "Color Wonder" markers contain colorless dyes that only display color when used to mark on special "Color Wonder" paper. These markers make use of leuco dyes that only develop color in the presence of acid. These markers provide science educators with a novel chemical system that can be implemented in inquiry-based…

White light refracted by a glass edge or a prism might be split into the colors of the rainbow but, when restricted by a suitable arrangement of edges, might also yield a sequence of colors complementary to the rainbow. We studied the creation of these color fields experimentally with a setup consisting of RGB light-emitting diodes that cover all…

Undergraduate-level laboratory experiments that integrate multidisciplinary chemistry concepts into a single activity are very appealing and thought-provoking for chemistry students. Here, we use the oscillating chemical reaction to introduce students to the analytical detection concept. The Belousov-Zhabotinsky reaction is employed as a simple…

Raman scattering is a powerful tool for revealing the vibrations of molecules, but as a nonlinear optical phenomenon, its signals can change via mechanisms like resonance enhancement that have no direct analogue in infrared spectroscopy. In this work, complementary measurements conducted on 4-nitrophenol and its conjugate base allow students to…

The laboratory experiment presented here describes the use of a calcium ion-selective electrode (Ca-ISE) to determine the concentration of zinc in a supplement tablet. This approach was developed to show students how to expand the range of applications of Ca-ISE to enable the determination of metal ions other than Ca[superscript 2+]. To determine…

Stimulating interest in science at an early age is important for STEM education. This work details an educational activity utilizing the anthocyanins found in butterfly pea flowers ("Clitoria ternatea"). This activity was developed for use in official classroom settings, online, and/or at-home with parental or educator guidance. Primary…

Pulse oximetry has become the standard of care in operating rooms, intensive care units, and hospitals worldwide. A pulse oximeter continuously and noninvasively monitors the functional oxygen saturation of hemoglobin in arterial blood (Sa[subscript O2]). Sa[subscript O2] is so important in medical care that it is often regarded as a fifth vital…

Many of us teach that insects can see "invisible" ultraviolet light, but what demonstrations do we perform to illustrate this? Often UV can be used to cause fluorescence or phosphorescence, which can make its existence more visible. But, is it possible to create photographs or videos that convincingly illustrate the vision of insects? In…

Diffraction is an important phenomenon in physics. This paper describes using a scanning electron microscope (SEM) to produce cross-sectional images of iridescent seashells. When seashell cross-sections are viewed in a SEM, regular structure is seen. Seashells are a good example of a biocomposite material and good natural objects for introducing…

Nanochemistry is an important aspect of modern chemical science. Though few educational institutions teach nanochemistry as a formal course, general exposure of students to nanoscience is yet important. Thus, we present a nanochemical activity that could be used as part of many chemistry courses or laboratories based on ChemToy2. This activity is…

This paper demonstrates the use of smartphones in an experiment of light absorption and light scattering. The LED display and camera of the smartphone are used as the light source and as the detector, respectively. The color wheel is used to choose the color of the light source to be shone through the sample for analysis. The detector directly…