George M. Hopkins (1842-1902) wrote a series of articles on demonstrating physical phenomena in the "Scientific American" during the last years of the 19th century. These were collected in a book, "Experimental Science," that was first published in 1890, with revisions in 1892 and 1902. It must have been well received, for the…

The family resemblance approach to nature of science is receiving increasing attention by science educators since its inception about a decade ago. Many scholars of science education have contributed and continue to contribute to it not only theoretically but also by applying it empirically to a wide range of areas such as curriculum and textbook…

Ethanol (EtOH) is among the most consumed drugs in the world. The behavior of humans after ingestion of this drug is characteristic: At low doses it may be excitatory and at higher doses, it may induce depressant/sedative effects. Similar effects are observed in the zebrafish experimental model ("Danio rerio"), which has about 70%…

The helium-plasma (HePI) ionization mass spectrometry method was used to track the formation of reaction products and consumption of reactants by continually monitoring the vapors in the reaction headspace in real time. Two examples of the application procedure are presented here: a nucleophilic acyl substitution reaction and a 1,4-nucleophilic…

An introductory experimental course to teach and assess basic organic synthesis and identification skills has been designed. The first work of this course, which is based on the well-known hydrazone formation reaction of benzaldehydes with Brady's reagent, is presented. The designed experiment has many advantages and perfectly matches the goal of…

Quinacridone red and violet are visually different colors, an observation confirmed by their visible reflectance spectra and CIE L*a*b* coordinates. However, their IR spectra are extremely similar. Though chemically identical, the two quinacridones are polymorphs. In this experiment, designed for and tested by nonscience majors, the pigments are…

Conventional mobile phone colorimetry usually utilizes the RGB color mode to measure concentration of solutions, but the paper entitled "Determining the Amount of Copper(II) Ions in a Solution Using a Smartphone" proposes the use of hue ("H") to measure the concentration. It is pointed out that the "H" value increases…

Gravity bends light. One can argue this by reasoning that a beam of light should travel in a curved path when viewed from within an accelerating frame of reference, and then invoking Einstein's principle of equivalence, which asserts that the effects observed in an accelerating frame of reference are indistinguishable from the effects observed in…

What happens when a perfectly elastic ball collides with a completely inelastic ball? It is shown that the outcome depends on the stiffness of each ball. A standard textbook problem in mechanics is to calculate the outcome of a head-on collision between two balls using conservation of momentum and kinetic energy. It is easily shown that the…

We demonstrated that an optimally designed pinhole camera can be used as an astronomical tool to observe the libration and apparent diameter change of the Moon at night. The libration and apparent diameter change of the Moon were observed using a handmade pinhole camera with a diameter of 0.65 mm and a focal length of 400 mm. It was found that the…

This study investigated the interrelationships among science process skills (SPSs) developed through home-based experiments (HBEs) and examined the correlation between SPS and science literacy (SL) among middle school students. Employing a qualitative correlational design, the study involved 77 seventh-grade students in Aceh Province, Indonesia.…

A renewed experimental procedure for the unknown carbonyl experiment has been developed using hydrazone synthesis, thin layer chromatography (TLC) analysis, and melting point determination to differentiate between structurally similar ketones and aldehydes in undergraduate organic chemistry practical courses. Benzaldehyde, p-tolualdehyde,…

Practical experiments enhance students' understanding of basic concepts and promote deep learning experiences in chemistry. The smartphone application of Lab4Chemistry was utilized to replace colorimeters with smartphone camera sensors. Low-cost and readily available materials, including anthocyanin (fresh red cabbage) and common kitchen…

Chemical engineers must learn to connect concepts across vastly different scales, spanning from molecular structures to industrial processes. Here, we explore the use of a virtual-reality simulation with a companion video of an experiment to help undergraduate students connect nanoscale fundamentals to macroscale engineering observations.

In this two-session experiment for an organic chemistry lab, students prepare a macrocyclic host compound--namely, a pillar[5]arene--by means of a templated 1,4-dimethoxybenzene/formaldehyde cyclo-oligomerization (session 1), and then, they explore its molecular recognition properties toward the 1,8-diaminooctane guest with the aid of [superscript…