The accumulation of urban sewage sludge is an environmental problem to which solutions must be sought. One of the ideas proposed in this paper is to turn it into glass. Thus, from a 'useless' product we obtain a new, more valuable material. This solution addresses two environmental aspects and a conceptual one, because in order to understand the process it will be necessary to introduce new concepts related to crystalline and amorphous material, and this allows us to make a comparison with glass formation in natur
