The world is going through a climate crisis that is severely impacting the environment and the well-being of the population. The increased consumption of plastics, especially in developing countries, is generating an exponential rise in plastic waste. This article introduces a qualitative investigation in the form of a case study, with data derived from an educational project focused on plastics as a vehicle for environmental education. This project was implemented with a group of 50 children from a Ghanaian school. Our results reveal that the students acquired a high level of knowledge of plastic and its properties, made possible by an active, globalizing, experimental methodology. This knowledge was later reinforced through the fabrication of materials for learning and play made of recycled plastic waste. Through this project, the participating students practiced critical and democratic global citizenship aimed at creating a sustainable world through an ecological perspective.