A laboratory experiment for the determination of the cross-linking density of silicone elastomers is described on the basis of swelling experiments and mechanical tests. In the experiment, the macroscopic swelling and mechanical behaviors of the elastomers were discussed as a function of the cross-linking density, which can be easily controlled by…

Flavor plays a crucial role and is the most important aspect of foods and beverages. [Beta]-Ionone is a common flavor compound with a characteristic violet-like odor. An undergraduate flavor compounds chemistry laboratory that provides preparation and characterization of the flavor compound inclusion complex between…

In this laboratory experiment, students apply a mass-based approach to determine the Henry's law constant for CO[subscript 2] using a small bottle of a diet carbonated beverage. The calculations are challenging; therefore, team-based learning is encouraged. Our students reported values of 0.033 ± 0.003 mol/(L[middle dot]atm) at room temperature…

This laboratory experiment introduces students to an important reaction in biomass valorization and allows them to gain a practical understanding of green chemistry. Acid-catalyzed dehydration reactions of fructose to 5-hydroxymethylfurfural and thus humins were performed both with and without aqueous solvent, along with two different catalysts…

This paper describes a new lab experiment where students explore the magnetic force on a permanent magnet placed inside a short solenoid. This lab is the fourth experiment performed in the second semester of the calculus-based introductory physics course at Washington University in St. Louis. The experiment is performed using a speaker (which…

Transcription is the critical first step in expressing a gene, during which an RNA polymerase (RNAP) synthesizes an RNA copy of one strand of the DNA that encodes a gene. Here we describe a laboratory experiment that uses a single assay to probe two important steps in transcription: (1) RNAP binding to DNA, and (2) the transcriptional activity of…

The presented article is dedicated to a new way of teaching substitution in algebra. In order to effectively master the subject matter, it is necessary for students to perceive the equal sign equivalently, to learn to manipulate expressions as objects, and to perceive and use transformations based on defining their own equivalences. According to…

The design and analysis of experiments (DOE) has historically been an important part of an education in statistics, and with the increasing complexity of modern production processes and the advent of large-scale online experiments, it continues to be highly relevant. In this article, we provide an extensive review of the literature on DOE…

While elimination reactions are ubiquitous in organic chemistry textbooks, their implementation in undergraduate laboratories still suffers from a lack of reliable and easy setup procedures. This paper describes an easy-to-implement set of elimination experiments in the pentanol and bromopentane series using a modified Hickman distillation head.…

An activity is described that uses simple materials and an easy-to-perform protocol to estimate the Curie temperature of nickel, which is the temperature at which nickel loses its ferromagnetism. To do so, an object made of nickel metal is heated with a lighter until it loses its ferromagnetism. The metal is allowed to drop into a beaker that…

We have developed a guided-inquiry laboratory exercise in which students perform viscosity measurements to infer the structure of poly(vinyl alcohol) (PVA) in aqueous solution. The activity combines both experiments and modeling. In the experimental portion of the exercise, students measure the viscosity of several solutions of PVA with differing…

In this laboratory experiment, a guided inquiry exploring the physicochemical principles of the dissolution of Ca(OH)[subscript 2](s) in water is proposed for laboratory classes in university and high school. As part of students' inquiry, two experimental approaches are used. One is the change in solubility with temperature revealed by measuring…

The COVID-19 pandemic and its related restrictions forced the reorganization of learning methodology and gave a central role to remote learning. Laboratory experiments are the most affected activity, and several alternatives were described. This work proposes to create calculation tools by simply programming in Visual Basic of Excel to emulate the…

Electrochemistry is taught in most undergraduate chemistry programs. Although this topic is important for students due to its broad interest in industry (energy, diagnostics, car industry, etc.), they often find it difficult, because it is based on a combination of various physical concepts such as electric fields, interfacial processes or charge…

The construction and characterization of a glucose biosensor has been implemented in an instrumental chemical analysis course to provide students experience with chemical sensing, electroanalytical methods, and flow injection analysis (FIA). The glucose biosensor was assembled on a glassy carbon electrode by depositing a layer of Prussian blue…