The resonance phenomenon is widely known in physics courses. Qualitatively speaking, resonance takes place in a driven oscillating system whenever the frequency approaches the natural frequency, resulting in maximal oscillatory amplitude. Very closely related to resonance is the phenomenon of mechanical beating, which occurs when the driving and…

Analysis of mercury in fish is an interesting problem with the potential to motivate students in chemistry laboratory courses. The recommended method for mercury analysis in fish is cold vapor atomic absorption spectroscopy (CVAAS), which requires homogeneous analyte solutions, typically prepared by acid digestion. Previously published digestion…

From a Cartesian perspective of rational analysis, the electric potential difference across the cell membrane is one of the fundamental concepts for the study of physiology. Unfortunately, undergraduate students often struggle to understand the genesis of this energy gradient, which makes the teaching activity a hard task for the instructor. The…

In the typical "cookbook" experiment comparing the radiation absorption rates of different colored surfaces, students' hands are commonly used as a measurement instrument to demonstrate that dull black and silvery surfaces are good and poor absorbers of radiation, respectively. However, college students are often skeptical about using…

A chemical engineering PhD student from Purdue University completed an internship at The Dow Chemical Company, evaluating the effect of scale on the hydrodynamics of a trickle bed reactor. A unique aspect of this work was that it arose from an ongoing collaboration, so that the project was within the scope of the graduate student's thesis. This…

Qualitative questions are proposed to assess the understanding of solubility and some of its applications. To improve those results, a simple quantitative problem on the precipitation of proteins is proposed.

A simple mathematical formulation of Mach's principle is given based on a century of investigation into inertia, and used to check the results of Newton's famous bucket experiment.

An activity is described wherein students observe dynamic floating and sinking behavior of plastic pieces in various liquids. The liquids and solids are all contained within a plastic bottle; the entire assembly is called a "density bottle". After completing a series of experiments that guides students to think about the relative…

In this paper we consider the main properties of cylindrical lenses and propose several demonstrational experiments that can be performed with them. Specifically we use simple glasses full of water to demonstrate some basic geometrical optics principles and phenomena. We also present some less standard experiments that can be performed with such…

An adaptable multistep synthesis project designed for the culmination of a second-year organic chemistry laboratory course is described. The target compound is a terphenyl derivative that is an intermediate in the synthesis of compounds used in organic light-emitting devices. Students react a conjugated diene with dimethylacetylene dicarboxylate…

This article deals with a modern version of Kundt's tube experiment. Using economic instruments and a couple of smartphones, it is possible to "see" nodes and antinodes of standing acoustic waves in a column of vibrating air and to measure the speed of sound.

A simple experiment is presented in which the spacing and geometric pattern of pixels in mobile displays is measured. The technique is based on optical constructive interference. While the experiment is another opportunity to demonstrate wave interference from a grating-like structure, this can also be used to demonstrate concepts of solid state…

Almost everyone will have observed a spinning coin fall to a shuddering stop. How and why does it do that? Several experiments are described, suitable for a student project, to help motivate an understanding of the rotational dynamics involved.

This is the third paper in our Light-Emitting Diodes series. The series aims to create a systematic library of LED-based materials and to provide the readers with the description of experiments and pedagogical treatment that would help their students construct, test, and apply physics concepts and mathematical relations. The first paper, published…

A simple experiment in relating a time-dependent linear acceleration function to height is explored through the use of a smartphone and an elevator. Given acceleration as a function of time, a(t), the velocity function and position functions are determined through integration as in v(t)=? a(t) dt (1) and x(t)=? v(t) dt. Mobile devices such as…