Activity for Examining Light Reflectance, Transmittance, and Absorbance with Textiles and Light-Emitting Diodes

Recent research has demonstrated the unambiguous positive effects of active learning in a variety of college-level courses. We report the implementation and assessment of a 50 minute active-learning in-class activity to conceptualize light absorbance, reflectance, and transmittance, coupled with a writing-to-learn exercise. The activity is suitable in a classroom setting using portable hand-held sensors and samples, including textiles and food-dye solutions. The assessment of the activity included a quasi-experimental design, in which 116 students in an introductory university chemistry course completed the activity, with outcomes compared to a different section, including 322 students, without the active-learning exercise. To determine the efficacy of the activity, students' written reports and exam assessment items relating to reflectance, transmittance, and absorbance were evaluated. With the assessment questions showing statistically significant improvement, it was concluded that the hands-on activity was effective in helping the students better understand the relationships among the three properties of light.