The Luminescent Lunchbox: Translating Research on Edible GRAS Probes into an Educational Kit in Photophysics

Abstract

Current research on generally recognized as safe (GRAS) luminescent food components can be used as an effective tool to explain the electromagnetic spectrum and its use in luminescence spectroscopy to elementary and middle school students.This project translates our research on food fluorescence into an educational kit, the “Luminescent Lunchbox”, with instructions and supplies necessary to conduct four photophysical-related activities:1-“Light Show”: students explore the concepts of energy, frequency, and wavelength by measuring the temperature of different colored LEDs whose irradiance wavelength was characterized at a reference lab. Students interpret results to establish the inverse correlation between wavelength and temperature.2-“Fluorescent Food Scavenger Hunt”: students are introduced to fluorescence and its extensive occurrence in biological samples by photo-exciting selected foods and observing their fluorescence emission. They are also encouraged to further explore food fluorescence through a scavenger hunt for luminescent foods in their own homes and report findings on a citizen science website.3-“Rainbow Ghosts”: students are provided with instructions and materials to build a simple spectrofluorometer out of a diffraction grating, LED lights and a common camera phone. Upon photoexcitation of a food or material with a LED light, the emission can be characterized using the cell phone. The predominant colors in the spectrum that appear on the cell phone screen correspond to the fluorescence emission band of the samples.4-“Shine Refine”: the spectra observed in the previous activity are enhanced by using gelatin-cast absorptive filters. The utilization of properly selected filters allows the student to obtain sharper spectra of the food samples, effectively eliminating the contribution of the light source.The “Luminescent Lunchbox” educational kit aims to help students understand the conditions, applications, and limitations of luminescence in the context of scientific research.