With the advancements in broad-spectrum sunscreens and the recent bans on benzene-based sunscreens due to their environmental toxicity, there has been a push toward broad-spectrum sunscreens containing in organic active ingredients. In this study, a procedure was developed to analyze the particle size and size distribution of inorganic active…

This paper has two parts. In the first part, intended for physics students as well as for engineering students whose primary interest is not physics, a new lesson related to shadow properties is given as a part of lectures on light. The effects resulting from a shadow 'motion' observed on a screen were looked into. The relationship between the…

Conceptual knowledge is a crucial tool for students to understand scientific phenomena. Knowledge about the structure and function of mental concepts potentially helps science educators to foster the acquisition of this tool. Specifically, the coherence of students' mental concepts is an intensely discussed issue within the related conceptual…

In this paper a sequence of nine, easy to manufacture optical black-box experiments with increasing levels of difficulty, and supportive frameworks for physics classes are introduced. They have been evaluated in a lower-secondary school at the end of optics lessons. A black-box is a kind of experimental task where the inner structure is not…

This study focuses on elucidating and explaining reasons for the stability of and interrelationships between students' conceptions about "Light Propagation" and "Visibility of Objects" using contextualized questions across 3 years of secondary schooling from Years 7 to 9. In a large-scale quantitative study involving 1,233…

To help students develop an understanding of the proper use and function of spectrographs and monochromators we describe a student-assembled spectrograph using a "webcam" detector. The apparatus also works well as a low-cost demonstration, helping students make connections between an atomic spectrum observed by eye and a plot of the relative…