A flipped classroom experience: Towards the knowledge of new ecofriendly materials named 'geopolymers'

Technological advances have impacted almost every facet of modern culture and even in the educational methodologies. As new technologies become available, they are often embraced in educational innovation in an attempt to enhance traditional instruction. To this purpose, the “flipped classroom” is a learning model in which content attainment is shifted forward to outside of class, then followed by teacher-facilitated concept application activities in class. The constructivist approach, realized through an active-learning style of teaching, is more important respect to the order with which the teacher participated in the learning process. In this respect, the goal is to provide an alternative teaching approach on environmental issue. In particular, thanks to active learning (flipped classroom) it is possible to know and to appreciate a new \textit{eco-friendly} material named to “Geopolymers”. One of the most important environmental advantage that can be attributed to this material is represented by the lower energy requirements for its production. Thus, this material could represent a potential tool able to mitigate the environmental pollution. In this regard, the geopolymers could provide a possible solution to wastes reuse as a resource to scale down the demand for extraction of new resources. This paper looks at some positive aspects of technology and waste treatment, and deals with the production of innovative building materials obtained by waste recycling known as geopolymers. Specifically, it is important to highlight the possibility of using wastes characterized by high silica and aluminum amounts as raw materials, particularly suitable to produce geopolymers by chemical activation with alkali. This is a useful method to improve hazardous-waste management and to reduce health and environmental issues due to the strong capability of make inert hazardous waste. This solution confirms the importance of re-manufacturing, reusing and recycling and, moreover, making a waste a new raw material and helps to move toward a more circular economy where wastes become negligible and further natural resources are used in an efficient and sustainable way. The proposed topic is addressed to students and aims to arouse their interest in the fields of the environmental protection and waste management, but overall it gives the perspective of natural resource preservation, and a most efficient way of their use without depleting the planet's resources.