Glowing-in-the-Screen: Teaching Fluorescence with a Homemade Accessible Setup

Teaching fluorescence aims to deeply communicate light–matter interactions. The main fluorescence concepts are covered in undergraduate courses and are difficult to comprehend as the proper lighting conditions for seeing it by the naked eye are rarely found in daily life. Here, we present a lab activity to explore fluorescence using homemade equipment in order to complement the teaching of the basics of fluorescence and perform typical experiments. This device consists of a cardboard box as fluorometer with a flashlight as an excitation source and a smartphone camera with an application for color analysis as a detector. The presented assays can be used in diverse teaching environments to reinforce the universal concepts of fluorescence, Stokes shifts, quenching, and the inner filter effect. The assays are based on common products (such as green leaves, turmeric, tonic water, and salt), so access to the materials and waste generation are not a problem. The results, robustness, and reliability of this setup were discussed after evaluating the comments of teachers and students who perform the lab experiences. Furthermore, the performance of the students was assessed using a survey, which demonstrates this is an excellent approach to increase their interest and motivation for learning.