Despite extensive conceptualization of ions as hard spheres in most textbooks, solid-state structures are more accurately modeled as overlapping soft spheres that better reflect the size of the ions. The corresponding soft-sphere ionic radii of alkali and halide ions can be empirically established from the partial molar volume of the ions in…

This study focuses on the experimental demonstration of the definition of kelvin using a triple point of water (TPW) cell and estimates the measurement uncertainty. The first part of this article is to construct the measurement setup and perform the measurements. The second stage is related with the calculation of uncertainty according to guides…

The development of an enzyme-mediated reaction for the first-year general, organic, and biological chemistry (GOB) teaching laboratory is of significant importance so that the factors that affect enzyme-mediated reactions can be adequately demonstrated, reinforcing the lecture portion of the GOB course. Some of the factors that affect these types…

This laboratory experiment introduces the fundamentals of electrochemical techniques to the undergraduate students by developing a simple and cost-effective miniaturized electrochemical setup for detecting UV-induced DNA damage. This is an imperative experiment, as it provides students first-hand experience with electrochemical techniques while…

Mass spectrometers are ever-increasingly powerful, user-friendly, and affordable. Thus, the addition of mass spectrometry experiments into the undergraduate laboratory curriculum is now both feasible and an effective tool to introduce students to relevant instrumentation. Here an experiment demonstrating the use of a high-resolution electrospray…

In the light of own measurements on a Faraday generator, the well-known theories concerning Unipolar Induction and the Faraday paradox seem to be problematic. On the other hand, all results obtained, and all other processes described as a paradox in connection with the Faraday generator can be explained without contradiction based on the theory of…

Two balls on an incline can remain at rest if friction between the balls prevents them rolling down the incline. Results with various balls are presented to show how ball mass, diameter and friction affects the outcome. A stack of four identical balls is also examined.

Carbonated beverages have long provided chemical educators and other teachers of science with an easy-to-obtain system that connects to several physicochemical concepts. For example, many educators have devised experiments to determine the pressure of CO[subscript 2] contained in commercial carbonated beverages, but the role of temperature in such…

A previous journal article established that a hanging Slinky's restoring force is due only to the coils between the support and the Slinky's center of mass (hereafter COM). Correspondingly, it is expected the Slinky's elastic potential energy (hereafter EPE) is associated with only those coils; however, there is no confirming experimental…

According to Einstein's general theory of relativity, a clock runs more slowly if it is close to a large gravitating object. This principle was highlighted in the movie "Interstellar," in which the main character spends several hours on a planet orbiting a massive black hole, and returns to find that his young daughter has become an…

A versatile experiment is described for the high school and college laboratory setting based on the synthesis of biobased polymers prepared from inexpensive, renewable, and nonhazardous chemicals. Combinations of readily available citric acid, glycerol, and tapioca root starch are used to prepare three polymeric materials with different observable…

Regioselectivity in hetero Diels-Alder reactions can be observed in a simple reaction between a nonsymmetrical heterodiene and an unsymmetrical heterodienophile. A 9 h and easy to implement laboratory experiment is described, in which students can observe the regioselectivity of inverse "electron-demand" hetero Diels-Alder reactions of…

Typical laboratory exercises for undergraduate organic chemistry students involve bulk phase reactions with work up of product. In this study, students performed accelerated versions of the Katritzky reaction of para-substituted anilines with pyrylium salts in three ways: (i) by dropcasting reagents onto a paper surface and allowing solvent to…

In the present study, atmospheric pressure, an abstract concept that learners generally have difficulty understanding and explaining, was presented to pre-service elementary teachers (PSTs) with the method of argumentation. The argument levels of the PSTs were examined using the Predict-Observe-Explain (POE) experiments in teaching the subject of…

The synthesis of a [2]rotaxane through three- or five-component coupling reactions has been adapted to an organic chemistry experiment for upper-division students. The experimental procedure addresses the search for the most favorable reaction conditions for the synthesis of the interlocked compound, which is obtained in a yield of up to 71%.…