Two introductory organic chemistry laboratory experiments are described based on the Diels-Alder reaction of 2,3,4,5-tetraphenylcyclopentadienone, which is synthesized prior to or in a one-pot reaction, with styrene. Students are presented with three possible products, the "endo" and "exo" diastereomers and the decarbonylated…

Transition metal organometallic reactions have become increasingly important in the synthesis of organic molecules. A new approach has been developed to introduce organometallic chemistry, along with organic and inorganic chemistry, at the foundational level. This change highlights applications of organometallic chemistry that have dramatically…

The transport of molecules across biological membranes are critical for most cellular processes. Membrane permeability is also a key determinant for drug absorption, distribution, and elimination. Diffusion, that is, the migration of matter down a concentration gradient, is a simple mechanism by which both endogenous and drug molecules can enter…

Calculating the effective resistance of an electrical network is a common problem in introductory physics courses. Such calculations are typically restricted to two-dimensional networks, though even such networks can become increasingly complex, leading to several studies on their properties. Furthermore, several authors have used advanced…

A laboratory experiment was developed to follow the gelation of a polyvinyl alcohol (PVA) solution upon addition of borax by using rotational viscometry. The rheological properties of the gel were examined, measuring the dependence of viscosity and shear stress on the shear rate. Time-dependent studies were also conducted in which the viscosity of…

The Characterization and Analysis of a Product (CAP) project is used to introduce first-semester general chemistry students to chemical instrumentation through the analysis of caffeine-containing beverage products. Some examples of these products have included coffee, tea, and energy drinks. Students perform at least three instrumental experiments…

This article describes an alternative method to determine the refractive index of transparent liquids. The method only requires a laser pointer, a ruler and a modified fish tank.

Optimal foraging theory attempts to explain the foraging patterns observed in animals, including their choice of particular food items and foraging locations. We describe three experiments designed to test hypotheses about food choice and foraging habitat preference using bird feeders. These experiments can be used alone or in combination and can…

Instructors often present Mendelian genetics and molecular biology separately. As a result, students often fail to connect the two topics in a tangible manner. We have adopted a simple experiment to help link these two important topics in a basic biology course, using red and white onions bought from a local grocery store. A lack of red coloration…

In science education, conventional problem practice hardly helps students reach "conceptual understanding" with which they can solve various problems by making appropriate models of target systems. Students often superficially read the solution of a problem and apply it wrongly to others without understanding the model. It is difficult…

In this note we synthesize and extend expressions for the magnetic field at the center of very short and very long current-carrying coils. Elementary physics textbooks present the following equation for the magnetic field inside a very long current-carrying coil (solenoid): B[subscript sol] = µ[subscript 0] (N/L) I, (1) where I is the current, N…

The solvent influence on the absorption spectra and the kinetics of the back reaction of the 1',3'-dihydro-1',3',3'-trimethyl-6-nitrospiro(2H-1-benzopyran-2,2'-2H-indole) (6-NO2-BIPS) has been investigated by means of temperature-controlled, UV-visible spectroscopic measurements. The back reaction process was proved to follow first-order kinetics…

An inexpensive procedure for introducing the Suzuki-Miyaura coupling reaction into a high-enrollment undergraduate organic chemistry laboratory course is described. The procedure employs an aqueous palladium solution as the catalyst and a range of para-substituted aryl bromides and arylboronic acids as substrates. The coupling reactions proceed…

Measurement of protein denaturation and protein folding is a common laboratory technique used in undergraduate biochemistry laboratories. Differential scanning fluorimetry (DSF) provides a rapid, sensitive, and general method for measuring protein thermal stability in an undergraduate biochemistry laboratory. In this method, the thermal…

The double-tangent construction of coexisting phases is an elegant approach to visualize all the multiphase binary systems that satisfy the equality of chemical potentials and to select the stable state. In this paper, we show how to perform the double-tangent construction of coexisting phases for binary systems modeled with the gamma-phi…