In this paper, we present simple demonstrations aimed at explaining the fundamental principles of the photoacoustic effect. To display the audible phenomenon that occurs as laser radiation gets absorbed by ethene gas, an optical chopper was used to modulate the power of a continuous-wave laser whose beam was directed into a gas. The absorbed…

Research-based assessments (RBAs) measure how well a course achieves discipline-specific outcomes. Educators can use outcomes from RBAs to guide instructional choices and to request resources to implement and sustain instructional transformations. One challenge for using RBAs, however, is a lack of comparative data, particularly given the skew in…

This study aimed at determining the category and analyzes the mental models of the students from three senior high school clusters (low, medium, high) on the solubility and solubility product topic, knowing students' opinions on chemistry subject, knowing learning methods and assessment that teacher used in solubility and solubility products…

The purpose of this study was to establish the factor structure and dimensionality of the Metacognitive Orientation Learning Environment Scale -- Science (MOLES-S) in the Thai context. The metacognitive orientation of a science classroom learning environment is defined as the extent to which psychosocial conditions that are known to enhance…

This study aimed to explore what kinds of epistemological messages were conveyed through teacher discourse in modeling-based and traditional elementary science classrooms and how teachers framed the two classrooms distinctively through these messages. Data came from two sixth-grade teachers' science classrooms--one characterized as a…

Biochemistry primarily focuses on the non-metal chemical elements carbon, oxygen, nitrogen, hydrogen, sulfur, and phosphorus in the four groups of building blocks (sugars, lipids, amino acids, and nucleotides) and the corresponding macromolecules. However, at least 10 essential chemical elements of life are metals. This article discusses the…

The use of mass spectrometry (MS) is becoming widespread and rather routine in all levels of industry, government, and academia. Coupled with chromatographic methods, this powerful instrumental technique can be used to elucidate the composition of a complex sample and definitively identify constituents while offering the benefits of high-precision…

Purpurogallin (PPG), an orange-red crystalline compound from nutgalls and oak bark, is an exemplar of numerous, ubiquitous natural colorants, biosynthesized through oxidative dimerization-decarboxylation of phenolic compounds. It possesses antioxidant, anticancer, and anti-inflammatory effects. Herein, a robust method is presented to allow…

In this experiment we have first determined the focal length of an equiconvex lens. We have observed that a real image can be formed by the lens on the same side of the source if the source is sufficiently strong. This is due to the reflection from the concave surface of the lens. We have measured these image distances for different object…

The refractive index (RI) is probably the single most important parameter in optical systems. Chromatic dispersion, on the other hand, indicates how the RI depends on the wavelength and is central in, e.g., optical communication systems. Chromatic dispersion also plays an important role when teaching optics due to the captivating natural…

The wave nature of light has been widely demonstrated in a double-slit experiment, which has played a special role in physics teaching. When monochromatic light passes through the double-slit sheet, the diffraction and interference fringes can be observed in the far-field regime. The interference of light causes the beams passing through the two…

Measurements and calculations are presented showing how the trajectory of an object sliding across an inclined plane varies with the launch and incline angles. The trajectory depends on the magnitude and direction of the sliding friction force. The experiment is easy to set up, can be analysed using a video camera, and would be suitable for a…

A simple method to determine Lewis electron dot structures and formal charges without a need to sum all of the valence electrons, reorganize electron pairs, draw and pair up individual electrons, or remember a formal charge formula is described. The formal charge is determined by the group number (number of valence electrons) and the number of…

Students come into the classroom with a variety of background knowledge. Therefore, it is imperative that educators are able to help all students, regardless of their familiarity with the content. Since it can be challenging for some large enrollment classes to schedule recitation classes after lectures due to logistical constraints, this study…

The COVID-19 pandemic affected a large range of in-person education activities in Colombia. This created great limitations in academic performance for students with reduced access to communication technologies and deepened the educational gaps in the country. This was particularly true for sciences such as biochemistry. In Colombia, molecular…