During the hands-on laboratory experience, students were able to: (i) use their smartphones as a tool to obtain data, (ii) employ image analysis techniques using ImageJ to enhance their 365 of the adsorption process, its function as biosorbents, and its connection with absorbance in smartphone colorimetry, (iii) particle size analysis of the fish scales manually and calculation of the percentage of Cu²⁺ removal, and (iv) hypothesis testing. Students built a light box with white LED lights using cardboard, paper, glue, or tape. This experimental setup for image acquisition using ImageJ was able to distinguish color intensity in a linear manner across a range of standard The smartphone colorimetry demonstrated here offers a viable alternative for quantifying the concentration of copper(II) sulfate solutions, comparable to standard UV-Vis spectrophotometry. This approach enhances accessibility to colorimetric assays in introductory laboratories and those without 375 expensive equipment like spectrophotometers. Students were motivated by discovering that their smartphones could serve as effective analytical devices.