This paper presents a system for remote monitoring of turbidity data that can detect light intensity and temperature using a microcontroller and the Internet of Things. The system comprises a light dependent resistor and infrared temperature sensor interfaced with an ESP-12E microcontroller, a programmable data acquisition platform; together these…

Quantum dots (QDs) are useful for demonstrating the particle-in-a-box (PIB) model utilized in quantum chemistry, and can readily be applied to a discussion of both thermodynamics and kinetics in an undergraduate laboratory setting. Modifications of existing synthetic procedures were used to create QDs of different sizes and compositions (CdS…

The purpose of this paper is to present and discuss an alternative solution to an experimental problem given to high school students in the XXII Ibero-American Physics Olympiad held by Colombia this year. From the measurements of electric current and potential difference across a small tungsten filament lamp students should find the dimensions of…

This experiment prepares a large (M[subscript r]: 1821 g mol[superscript -1]) triple helicate complex quickly in one pot from inexpensive starting materials. The protocol illustrates the power of self-assembly in a simple manner that is suitable for second-year general chemistry students using reversible imine bond and metal-ligand bond formation.…

An introductory general chemistry laboratory course was developed to provide an authentic research experience in environmental chemistry. First- and second-year students learned general chemistry concepts and laboratory skills in the context of snow chemistry while participating in the course-based undergraduate research experience. Students were…

Designing and conducting sound and informative experiments is an important aspect of inquiry learning. Students, however, often design experiments that do not allow them to reach conclusions. Considering the difficulties students experience with the process of designing experiments, additional guidance in the form of an Experiment Design Tool…

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…

Laboratory reports written in the style of a standard scientific article are commonly used to assess student learning in biochemistry laboratory courses. While most students can complete the Materials and Methods or Results sections successfully, many have difficulty with the Introduction and Discussion. They fail to place their data in a larger…

The ability of certain organometallic reagents to react via 1,2- or 1,4-addition to an a,ß-unsaturated ketone is a fundamental example of regioselectivity at the second-year undergraduate organic level. The following two experiments were designed to demonstrate this preference by exploiting carvone as an inexpensive chiral, nonracemic substrate.…

An undergraduate experiment for the organic laboratory is described that utilizes microwave heating to prepare 5- substituted 1H-tetrazole derivatives through a (3 + 2) cycloaddition between aryl nitriles and sodium azide. The reaction mixture is analyzed by thin layer chromatography. The products are purified through an acid-base extraction and…

This paper describes an undergraduate laboratory experiment where students study the heating behavior of magnetic nanoparticles in the presence of alternating magnetic fields. Average score on the post-test was 45±12% for students who completed the lab online, versus 43±11% for those doing the activity hands-on. Post-test scores were significantly…

Practicing chemists use models, diagrams, symbols, and figures to represent phenomena which cannot be detected by the human senses. Although research suggests that these external representations (ERs) can also be used to address the challenges that students have in learning chemistry, it is not clear how instructors' use of ERs aligns with their…

A simple synthesis of fluorescent carbon quantum dots from lemon juice is described to introduce advanced high-school students and undergraduate college students to nanoparticle synthesis and quantum dots. The synthesis is based on the carbonization of lemon juice using only a hot plate stirrer. Column chromatography is used to separate different…

When sound waves are taught at the secondary level, the speed of propagation of sound is one of the most important characteristics to be analyzed. However, it is very common in textbooks that the value of sound speed in air is considered constant regardless of the experimental conditions. The great question is that since sound is a mechanical…

Practical skills in science education, defined as those developed through the observation, demonstration, manipulation, and application of scientific principles, valued in both academia and industry, feature conspicuously in curriculums the world over. Efficiently imparting such skills to students necessitates access to scientific equipment of…