where Iblank was the intensity of the water blank. 27 In this activity, a solution containing 400 ppm Cu 2+ was used. The average particle size of dried fish scales inside teabags was determined using ImageJ analysis on approximately 0.50±0.01 grams of dried fish scales before and after immersion in 20 cm 3 of copper(II) sulfate solution for 30 minutes. As a control, another fish scale teabag was immersed in 20 cm 3 of deionized water (absence of copper(II) ions, 180 as shown in Figure ). Subsequently, the fish scales were extracted from the teabags and air-dried for 1 hour. Photographs, with a ruler as reference, were taken by students from the top of the photography light box (Figure ). The students compared the average area (in cm 2 ) from two photographs of the fish scales (refer to the Procedure and Checklist in the Supporting Information for detailed procedures). The average data from all 10 groups of students were aggregated to produce Figure . Students compared their data using a non-parametric statistical test, the Mann-Whitney U test. The remaining copper(II) sulfate solution was retained for subsequent steps of the experiments. These measurements were conducted in triplicate.