A highly visual, inexpensive, straightforward laboratory experiment for the determination of the activation energy of a demulsification process is presented. The experiment uses low-density polyethylene (LDPE) beads to clearly mark the interface between an NaCl(aq) solution and isopropanol. The NaCl(aq)-isopropanol system is shaken to produce an…

The problem of a disc or cylinder initially rolling with slipping on a surface and subsequently transitioning to rolling without slipping is often cited in textbooks. Students struggle to qualitatively understand the difference between kinetic and static frictional forces--i.e., whereas the magnitude of the former is known, that of the latter can…

The crystalline sponge method allows for direct and precise molecular structure determination of liquid and gaseous targets and thus has been recognized as a revolutionary breakthrough in crystallography. To expose undergraduates to this cutting-edge technique, we have developed a comprehensive laboratory experiment with reaction conditions and…

The determination of the speed of sound in air is a classical experiment, usually performed with a resonance tube apparatus. The measured value can be checked against Eq. (1), which describes the temperature dependence of the speed of sound in dry air. A modern implementation of this speed of sound investigation uses an Arduino Uno microcontroller…

In order to fix some important concepts of Fundamental Physics, either because they are not usually discussed in depth in theoretical classes and much less at laboratories, or because they are not sufficiently developed in textbooks, it is more effective not to tackle them directly, but to propose a mental or practical experiment to attract the…

The laser pointer has been widely used to demonstrate some simple optics phenomena, like reflection, refraction, total reflection, and diffraction. However, the rays of laser light cannot be seen in the air because the scattered light is too weak. Many physics teachers use milk or smoke to visualize rays of laser light in physics labs, but it is…

This paper proposes a simple method to design experiments for drawing the light paths at a lens to find its effective focal length and principal planes. In the designed experiments, long-exposure photography was used to record the light scattered using a moving sheet of paper, thus revealing the light path. According to the proposed experimental…

Water rockets can be used in a variety of ways, from schools to planetariums, with very young kids or adults. We propose here simple forms to work with water rockets, going one step further than a simple launch. A smartphone can be used to film the launch and analyze its motion with video analysis or it can even be attached to the rocket, using…

A popular introductory physics laboratory experiment is one focusing on Snell's law. This is straightforward to complete with lasers and prisms, but here we present an alternative version that guides the students through some of the major historical developments, recreating and analyzing significant experiments. The discovery of Snell's law has a…

A successful scientific career requires competency in not only content knowledge but also professional skills, such as written and oral communication, decision making, problem solving, and planning, organizing, and prioritizing work. These professional skills are prioritized in the 2016 NACE Job Outlook report as the top 10 attributes employers…

A qualitative sugar identification laboratory was adapted from a hands-on experiment to a virtual "choose your own adventure" experience where students select virtual experiments to conduct on samples of known and unknown carbohydrates. Students select positive and negative controls for each qualitative test and compare results from the…

While the COVID-19 pandemic continues, the acceptance of numerous measures, such as mandatory wearing of face masks or social distancing, is declining. At the same time, the spread of fake news related to these measures is on the rise. The acceptance of and compliance with the measures depends to a large extent on knowledge about these very…

To present the difference in oxidizing strength in concentrated and dilute nitric acid reacting with copper, a simple, facile demonstration of these reactions is designed using a waste plastic bottle, plastic droppers, and syringes, which are costless and easily assembled. This new version can be used to demonstrate the difference in oxidizing…

So-called "Color Wonder" markers contain colorless dyes that only display color when used to mark on special "Color Wonder" paper. These markers make use of leuco dyes that only develop color in the presence of acid. These markers provide science educators with a novel chemical system that can be implemented in inquiry-based…

Nonlinear chemical reactions produce interesting chemohydrodynamic patterns in an unstirred medium, which act as interesting demonstrations to display the novel phenomena in a nonequilibrium chemical system. Here, we report new outreach experiments: pH chemohydrodynamic patterns modulated by sodium polyacrylate in the bromate-sulfite-ferrocyanide…