The book deals with the viscosity, fluidity and density of substances based on the concept proposed by the authors chaotical particles, allowing to display a solid, liquid and gaseous states of their unstructured component. As its basis the Boltzmann’s distribution of the kinetic (thermal) energy of the particles responsible for their chaotic state was taken. For the liquid state the regularities of change of viscosity, fluidity and density on temperature, as well as the mutual consistency and coherence with-in a united cluster and associate model without considering the specific structure of the clusters and associates, but with the determination of the proportion, size and other features on simple substances and some melts of complex composition are exposed. The book can provide theoretical and practical interest to chemists and metallurgists, as well as for those who wish to assess the role of the chaotic start-ray not only in a state matter, but in all things. As a textbook it is recommended to undergraduates, graduate students and doctorate in the field of "Physical Chemistry", "Inorganic Chemistry", "Theory of metallurgical processes".