Enhancing STEM Education by Integrating Research and Teaching in Photochemistry: An Undergraduate Chemistry Laboratory in Spectroscopy and Photochemistry

Photochemical reactions are the reactions that are induced by light. Many of these reactions are found in natural processes, including photosynthesis and the formation and decomposition of ozone in the atmosphere. Classroom demonstrations are effective in enhancing students' learning and retention. Herein, we have developed a simple demonstration of a photochemical redox reaction, which can be performed in a classroom or laboratory setting in schools and universities. This demonstration can be performed in both traditional and activelearning formats. A light-yellow solution containing ferric chloride, 2,2′-bipyridine, and sodium pyruvate, when exposed to visible light, produces a pink color that can be discerned within 3 min. The same reaction mixture kept in the dark does not produce a change in color, indicating that light is essential for this reaction. In the presence of light, pyruvate ions reduce ferric ions to ferrous ions, which then form a complex with 2,2′-bipyridine molecules, resulting in the production of a pink color. The intensity of the pink color increases with time, indicating the accumulation of products. This demonstration is simple, does not require a special source of light, and gives an excellent example of a photochemical redox reaction.

Section: Introductionmentioning

confidence: 99%

A Simple, Fast, and Facile Demonstration of a Photochemical Redox Reaction Using Visible Light

Regmi

Fleming

2023

Using Olive Oil as a Pedagogical Medium to Teach Ultraviolet Spectrophotometry

Shen,

Li,

Bong

et al. 2024

Teaching complex instrumental analysis with real-life applications is vital for enhancing students’ understanding and cultivating their interest in learning. This study utilizes olive oil as a pedagogical medium, offering educational insights into the practical applications of ultraviolet (UV) spectrophotometry for assessing edible oil quality upon thermal treatment. Through a questionnaire survey involving 197 undergraduate participants, this work aims to deepen the understanding of UV absorption techniques with practical relevance. It evaluates participants’ comprehension and proficiency in UV spectrophotometry analysis and discusses improvements in pedagogical approaches for teaching knowledge related to light absorption.

Analysis of Food Extracts with Thin Layer Chromatography: A STEM Outreach Activity

Ho,

Elizondo,

Urbiola

et al. 2024

An outreach activity was developed and performed where familiar food items (e.g., beverages, leaves, vegetables, and citrus peels) were extracted with ethanol or ethyl acetate, and the extracts were analyzed through thin-layer chromatography (TLC). The purpose of this activity was to teach participants how chemistry can be used in the real world. Sixteen participants, who were in eighth−12th grade, were divided into four groups with two pairs of individuals. Each group was led by a university student researcher from the advisor's laboratory or by the advisor. The food extracts were analyzed by TLC using solvent systems composed of ethyl acetate and cyclohexane on glass-backed TLC plates with silica gel. After the TLC plates were developed in the solvent chamber, the separated components were visualized using a stain. The pairs of participants repeated the TLC experiment for a second time by choosing their own extracts from different groups to analyze. This outreach activity was deployed at Girls Inc. of San Antonio to show STEM participants how chemistry techniques (extraction and TLC analysis) can be used to separate different compounds from natural sources.