Аннотация:Investigation of the mathematical physics equations, which describe material media such as thermodynamic, gas-dynamic and cosmic and other media, shows that they possess hidden invariant properties. Such properties correspond to that of field theory equations, which describe physical fields. This discloses a mechanism of physical fields generation by material media. Such specific properties of mathematical physics equations are connected with conservation laws. They are described by skew-symmetric differential forms which properties correspond to conservation laws.Keywords: conservation laws, evolutionary relation, the physical structures, unobservable quantityISSN: 2290-8887