Microplastics have been detected in most ecosystems around the world. They affect the environment and organisms in it, including humans and possibly their health. Hence, the analysis of microplastic occurrence in the environment is highly relevant. However, there are only a few practical and easy-to-implement methods published for school use, and therefore, microplastics still receive little attention in the classroom. This review presents an approach for separation and detection of microplastic particles in sediment with secondary school students based on methods used in current research. After sieving and density separation, the fluorescence marker Nile Red is used to selectively stain microplastic particles. Subsequently, the particles can be detected using a DIY low-cost fluorescence photobox. It offers an opportunity to address the problems associated with microplastics in a school context and can be used as an example for further discussion.