Anthocyanins are natural pigments belonging to the flavonoid family that generate the red, blue, and purple colors of fruits, vegetables, and flowers. Their structure and color are dependent on various factors, like the pH. Anthocyanins appear red in acidic, purple in neutral, and blue in basic solutions, making them suitable for use as natural pH…

A laboratory experiment has been developed to illustrate the transformation of silver nanoparticles (Ag NPs) in water containing phosphate anions. The experiment, conducted by high school students, involved hands-on learning to synthesize and characterize Ag NPs via ultraviolet-visible (UV-vis) spectroscopy. This was followed by a UV-vis probe of…

Recognition of interference and diffraction patterns is a difficult task for both high-school and university students. Many students fail to observe important features of particular patterns and identify the differences among similar patterns. In this study, we investigated if performing students' investigative experiments can help high-school…

An experiment is described that uses easily obtained materials (glow sticks, chalk, and acetone or alcohol) to separate the dyes contained in glow sticks that actively emit chemiluminescent light. The experiment is very easy to carry out, making it amenable for students to perform in laboratory or outreach settings. The separation occurs fast…

Pigments, dyes, and transition-metal compounds are made in courses across the undergraduate chemistry curriculum, but student characterization of these compounds' most striking features, their colors, seldom goes beyond verbal descriptions. Affordable, hand-held, fiber-optic reflectance spectrophotometers make it possible to advance students'…

Aqueous biphasic systems (ABS) composed of polypropylene glycol and carbohydrates, two benign substances are proposed to separate two food colorants (E122 and E133). ABS are promising extractive platforms, particularly for biomolecules, due to their aqueous and mild nature (pH and temperature), reduced environmental impact and processing costs.…

In selecting from a repertoire of traditional kinetics experiments, an instructor often has to choose among having students gain experience with the graphical method, the method of initial rates, or a temperature-dependent experiment in which students construct an Arrhenius plot. This paper presents an environmentally friendly bleaching reaction…

Low cost, open-source analytical instrumentation has the potential to increase educational outcomes for students and enable large-scale citizen science projects. Many of these instruments rely on smartphones to collect the data, mainly because they can effectively leverage a dramatic price-to-performance ratio of the optical sensors. However,…

One of the most mystifying products on the market for people at any age is the glow stick: a plastic tube that, when snapped, creates a flood of bright, brilliantly colored light without the use of electricity or significant production of heat. In this case, the chemiluminescence reaction also provides an exciting phenomenon through which we can…

The result of additive colors is always fascinating to young students. When we teach this topic to 14- to 16-year-old students, they do not usually notice we use maximum light quantities of red (R), green (G), and blue (B) to obtain yellow, magenta, and cyan colors in order to build the well-known additive color diagram of Fig. 1. But how about…

Surface-enhanced Raman scattering (SERS) studies of art represent an attractive way to introduce undergraduate students to concepts in nanoscience, vibrational spectroscopy, and instrumental analysis. Here, we present an undergraduate analytical or physical chemistry laboratory wherein a combination of normal Raman and SERS spectroscopy is used to…

The quantization of electronic energy levels in atoms is foundational to a mechanistic explanation of the periodicity of elemental properties and behavior. This paper presents a hands-on, guided inquiry approach to teaching this concept as part of a broader treatment of quantum mechanics, and as a foundation for an understanding of chemical…