A simple photometric device was built to measure the kinetics of the title reaction. The device consisted of a green light-emitting diode (centered at 520 nm), a sample vial, a photodiode, and an Arduino microcontroller board. These parts were mounted on a black poly(lactic acid) holder which was manufactured by utilizing three-dimensional…

The law of conservation of momentum is a fundamental law of nature. It states that the momentum of an isolated system is conserved. In high school or introductory-level physics courses, for simplicity, teachers and textbooks always use collisions in one dimension as the examples to introduce the concept of conservation of momentum. To solve simple…

The distinction between pressure in a liquid and in a gas is often treated in a cursory way, or not treated at all, even in university level textbooks. Most texts fail to point out the relation between pressure and density in a gas as compared to pressure in a--virtually incompressible--liquid. In many instances this also results in a dismissive…

Efforts to understand changes in teacher curricula following the adoption of reform-based standards, such as the "Next Generation Science Standards" (NGSS) remain incomplete and prior scholarship has identified several topics in the standards (e.g., nuclear chemistry and kinetics) that remain infrequently addressed in teachers'…

In this study, our aim was to identify high school and university students' post-instruction conceptions about the law of conservation of mechanical energy (LCME). A cross-sectional survey design was used. Firstly, a test consisting of 14 multiple-choice questions was developed. 23 physics teachers analysed the test and concluded that our…

What if "every breath you take, every move you make" (Sting 1983) could be harnessed to produce renewable energy? Triboelectric nanogenerators (TENGs) are state-of-the-art devices researchers are studying to do just that--convert kinetic energy into electrical energy at the source (Saurabh Rathore 2018). This type of electrical energy is…

Experimental results are presented on the collision of a superball with two different wood blocks. The results are in reasonable agreement with a simple collision model where kinetic energy is conserved, but better agreement is obtained if a small loss of kinetic energy is assumed, as observed. The physics is slightly more complicated than the…

The vertical bounce of a plastic egg was investigated by dropping the egg on a horizontal surface and filming the result with a video camera. If the egg is dropped on one end then it bounces just like a spherical ball. If the top end of the egg is pointing forwards or backwards when it lands on the surface, or if the egg is spinning when it lands,…

The video of a free-falling object was analysed in Tracker in order to extract the position and time data. On the basis of these data, the velocity, gravitational potential energy, kinetic energy, and the work done by gravity were obtained. These led to a rather simultaneous validation of the conservation law of energy and the work-energy theorem.…

A simple experiment for students is to measure the coefficient of restitution (COR) for a vertical bounce on a horizontal surface. In this paper, measurements are presented of the COR for a tennis ball bouncing at an oblique angle on a horizontal surface. Changes in the horizontal and rotation speeds were also measured, by filming the bounce with…

Scientific literacy is an important skill for students' success, given the characteristics of today's society. However, not all students have a natural predisposition toward science, chemistry in particular. Considering the relevance of transdisciplinary learning, schools should foster the scientific abilities for which students may have less…

In this paper we present a novel approach to teach kinetic energy as an observable and measurable concept. The fundamental principles have been outlined for gravitational potential energy in an earlier work, that we extend here. By accelerating or decelerating bodies with springs we begin, in a first step, with a direct comparison method for…

Most didactic lab experiments deal with the influence of temperature, concentration, pressure, surface area, and catalysts on chemical kinetics; however, few of them explore the influence of light radiation and the presence of inhibitor agents on reaction rates. In order to investigate the effects of the radiation source and the presence of…

This article introduces the use of "VPython" (the "Python" programming language plus a 3D graphics module called "Visual") as a potentially valuable tool in teaching aspects of secondary school chemistry, which also provides an opportunity for students to gain some experience with manipulating and/or writing computer…

Herein we present a modified iodine clock experiment which replaces starch with cellulose paper. This provides the reaction with a white solid surface in which color change can be clearly observed and reduces reagent amounts required to 540 µL per group. After data acquisition, students are required to calculate reaction orders and the reaction…