Controlling Type 1 error and encouraging reproducible research are important in clinical and translational research. These concepts are frequently discussed in lectures with mathematical language, analytic examples, and probability distributions that demonstrate the issues. However, first-time learners in biostatistics courses focusing on…

In this article, we will present the HEC BB bag, a simple but elegant model originally invented to help students imagine how air molecules move around in vacuum. The HEC BB bag is made by packing 20 to 30 BBs in a resealable plastic bag of several tens of square centimeters (see Fig. 1). When inflated fully via a straw, the volume of the bag is…

A simple, safe, and easy demonstration of the reaction of sodium peroxide with water is presented. The reaction is performed in a plastic bottle by adding water to sodium peroxide supported in a rubber "thimble"; oxygen is detected by the reignition of a glowing splint, while the generation of sodium hydroxide is indicated by…

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…

Principal Component Analysis (PCA) is a powerful statistical technique for reducing the complexity of data and making patterns and relationships within the data more easily understandable. By using PCA, students can learn to identify the most important features of a data set, visualize relationships between variables, and make informed decisions…

Millions of ha of sodic soils exist around the world and the movement of water through these soils is most directly dictated by the concentration of Na and overall electrical conductivity of the soil, and minerology of the clay. Helping farmers, land managers, crop advisors, and students better understand why water moves or does not move in these…

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…

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 formation of chemical patterns is in general difficult to control due to the random diffusive motions of the reacting chemical species in solution. In this paper, we present a new method using audible sound to control the formation of chemical patterns obtained in blue bottle experiments. The waves generated on the surface of the solution by…

Interactive classroom demonstrations (ICDs) are used extensively in physics, and prior studies indicate that, when conducted under certain conditions, they lead to appreciable increases in student gains and retention. The literature suggests that the ICD recipe for maximizing student gain is to (i) introduce the physical theory that will be…

Between April and December 1915, Maria Montessori and her son, Mario Montessori, spent time in California. Historical accounts of this period have emphasized Montessori's participation in San Francisco's world's fair, the Panama-Pacific International Exposition (PPIE), and identified this event as the crux of her travels. The following text and…

Sanger sequencing, also known as dideoxy sequencing, is a widely used method for DNA sequencing, particularly for cloned plasmids and clinical samples. This technique requires a combination of essential biochemistry skills, such as a chain-termination reaction, gel electrophoresis, and fluorescence detection. Unfortunately, there is a lack of…