A culinary exploration of the role of CO[subscript 2] in leavening is described. This demonstration substitutes dry ice for chemical leaveners in order to achieve the same pancake fluffiness. Under the universal framework of food and cooking, we developed this activity to bring aspects of phase transitions and chemical transformations to a broad…

The mercury beating heart is a classic demonstration to introduce redox reactions in the classroom. Here we report a new, safer demonstration: the Galinstan beating heart. Galinstan is a commercially available eutectic alloy composed of gallium (68.5%), indium (21.5%), and tin (10%) that has low toxicity. When an iron nail touches the Galinstan…

A key concept in current fluid dynamics and its applications to biology and technology is a phenomenon known as wetting. Wetting is familiar from everyday life and is simply the ability of a liquid to stay in contact with a solid surface. The wettability depends on the properties of the liquid and the solid and can be characterized by the static…

Interfacial, or surface tension, is a significant topic in chemical education. This paper describes the directional motion of gallium-based liquid metal drops, resulting from a difference of interfacial tension across the drop. This demonstration can engage students in discovering the underlying chemical principles. A mechanism for the drop's…

A simple demonstration adaptable to classroom conditions is presented, which involves the preparation of raffle tickets using filter paper and the solution of selected fluorophores. With an appropriate dilution, the text written on the tickets is not visible to the naked eye; however, it becomes readable once put under a UV lamp. Besides being a…

The simple demonstration presented, herein, involves the combustion of acetylene liberated from the rapid hydrolysis of 0.50 g of calcium carbide. The unsaturated hydrocarbon formed burns with a yellow sooty flame in air. This acetylene-air flame being visually attractive is often misused by those attempting to showcase their illusory magical…

The concept of "like dissolves like" is explored using a solvent extraction demonstration appropriate for first-year chemistry students. Equal volumes of aqueous methyl red and blue copper(II) sulfate form a purple solution. 1-Pentanol is added and floats on top as a clear layer due to its lower density and low water solubility. Vigorous…

A mixture of salt water and isopropyl alcohol is immiscible, forming two separate liquids with the organic layer on top and aqueous layer on bottom. When universal indicator is added to such a mixture, all of the indicator compounds in the universal indicator preferentially dissolve in the alcohol--except for phenolphthalein at high pH. Mixtures…

The movement of air into and out of the lungs is facilitated by changes in pressure within the thoracic cavity relative to atmospheric pressure, as well as the resistance encountered by airways. In this process, the movement of air into and out of the lungs is driven by pressure gradients established by changes in lung volume and intra-alveolar…

For decades, chemical modeling sets have allowed the user to manipulate atoms and bonds using plastic/wooden ball and stick materials. Here is a design for an interlocking toy brick modeling set in which the undergraduate nursing student can manipulate electrons during the simulated chemical bonding exercise. The author presents a teaching and…

Corrosion of metal, especially iron, is a natural electrochemical process that costs billions of dollars every year. Educating college and precollege students, our future STEM professionals, about the chemistry that governs corrosion and its prevention strategies is of paramount importance. In this manuscript, we share a few simple iron…

A 2.7 m long stringless pendulum was set up to measure the coefficient of rolling friction of various balls, at higher rolling speeds than usually observed with a short stringless pendulum. The arrangement is easy to set up and makes an impressive classroom demonstration as well as an interesting laboratory experiment.

Blue (B), yellow (Y), red (R), and green (G) color-changing dye was used in a general chemistry course for first-year undergraduate students with nonscience majors to highlight the redox reactions written as the gain and loss of hydrogen. The first experiment is a vibrant color variation using a synthetic dye of indigo carmine. The second…

Collective motion in living matter is highly intriguing but can also be observed in charged colloidal systems. Collective motion observed in colloidal systems requires extensive material synthesis, external stimuli, and advanced characterization methods that might be highly costly to be employed for teaching. Besides that, colloidal systems can…

Resonance is a widely observed physical phenomenon, occurring when an oscillator experiences a driving force whose frequency closely matches one of its own natural frequencies. Due to its broad applicability in physics, resonance is a familiar topic in the physics teaching literature. Previous studies include resonant energy transfer between…