Delusions versus reality in some physics problems: theory and experiment

The important problem of relation between theory and experiment in different physical problems is discussed. A number of examples, both widely and weakly known, are used to show that some physical theories, considered by many as correct because they corresponded to many experimental facts and to scientific level, have been found to be false. One of the more important reasons of this lies in the fact that it is very difficult to distinct the causes and consequences of phenomena observed in experiments. The best example is the study of turbulent flows, where causes and consequences are often erroneously interchanged in relation to the properties and development mechanisms of turbulence. At the same time some inverse examples are described, when phenomena that are impossible from the point of view of universally accepted theoretical concepts turn out to be a reality in special cases.