This work describes the design and testing of a low-cost light-emitting diode (LED)-based nephelometer for turbidity analysis. It also describes the use of this nephelometer for context-based learning (CBL) experiments designed for teaching laboratories. The LED nephelometer is simple, low-cost, and robust, providing similar results as a…

Drop Tower Physics (DTP) is composed of a set of experiments using standard physics lecture demonstration equipment, such as a pendulum, mass spring oscillator, and so forth, while videotaping them as they fall freely in the Dryden Drop Tower in Portland, OR. An article published in "The Physics Teacher" illustrated the behavior of a…

This paper outlines a comprehensive teaching laboratory course program that centers on titration analysis, a timeless and essential technique in analytical chemistry spanning various disciplines, such as environmental science, medicine, and industry. In these fields, titration analysis is paramount for determining the concentrations of substances…

In this article we present a simple experimental set-up to determine the band gap of germanium and silicon using the "ExpEYES-17" kit. The experiment is based on the temperature dependence of the reverse current through germanium and silicon diodes at different temperatures. The experimental values are found to agree well with accepted…

Technically simple and extremely cheap setups for colorimetric and fluorimetric analyses using a smartphone camera are presented. Laboratory activities on digital colorimetric and fluorimetric analyses for students of secondary and higher educational institutions are proposed, namely, photocolorimetric determination of acetylsalicylic acid in…

Recently, small computer fans have been demonstrated to be an effective method for teaching simple resistive circuits both qualitatively and quantitatively. The current through the fans is related to the rotational speed of the fans and allows multiple senses to be engaged (touch, sight, and hearing). Methods for learning simple circuits in an…

Student understanding of the laws that describe the flow of a fluid is often hampered by a defective knowledge of basic classical mechanics (kinematics, statics, dynamics, and conservation laws) and by wrong common-sense ideas about quantities related to fluids, such as velocity and pressure. A pedagogical discussion about the Venturi effect,…

Cola beverages are widely consumed and popular among students; they can be used as safe reagents to replace toxic chemical dyes. In this study, a safe and improved experiment is described, which successfully demonstrates Beer's law and adsorption process using activated carbon as the adsorbent and cola as the adsorbate. The results of this study…

This paper describes a very simple, but accurate method of finding the position of the infinity focus of a telescope objective relative to the rear face of its lens cell. The method is easily undertaken in the classroom and provides an opportunity for learners to conduct an interesting and novel optical experiment which introduces thick lens…

A simple apparatus consisting of a plastic syringe coupled with a U-tube has been constructed. This setup is filled with water to trap air in one arm of the U-tube. A change in the volume of the enclosed air causes a change in its pressure that is indicated by the difference in the water levels. Boyle's law is shown by a linear relation between…

For many historians of science and science educators, the method of replicating historical scientific apparatus and experiments provides an avenue for science learning, promotes critical and independent thinking, and fosters a deeper understanding of the nature of scientific practice. This paper presents a research study where a group of high…

We demonstrate that the simplicity of preparing functional microfluidic devices using 3D printing is well suited for undergraduate laboratories. Educational experiments utilizing non-paper-based microfluidic devices are often relegated to well-equipped, resource rich universities because traditional fabrication techniques require specialized and…

A pair of galvo mirrors reflecting light from a laser pointer is suggested for use as a school demonstration of Lissajous figures. The device is small, cheap and easy to assemble. Combined with a two-channel waveform generator, a full spectrum of excellently stable Lissajous figures can be generated (concerning frequency ratio, amplitude ratio and…

We present a versatile experimental apparatus for exploring rotational motion through the interplay between the moment of inertia, torque, and rotational kinetic energy of a wheel. The heart of this experiment uses a 3D-printed wheel along with easily accessible stock components that allow for the adjustment of the moment of inertia while keeping…

In this laboratory experiment, students performed thermogravimetric analysis (TGA) coupled with mass spectrometry (MS) of herbaceous materials (TGA-MS) and learned to analyze mass-loss curves, as well as identify common fragmentation ions. The experiment is the first one to present the application of TGA in a currently relevant topic: biomass…