The book is a continuation of the issues of “Essays” 2019 . and 2020. and includes materials reflecting different periods of activity of faculties of physical and mathematical profile of SSU. 125th Anniversary of the Nobel Prize N. N. Semenov is devoted to an essay that tells about his support for the direction of "Chemical Physics" at the SSU . The history of teaching astronomy and astronomical research at the university is presented, the peculiarities of study and leisure of students of the first half of the 1950s are described. Biographical articles cover the activities of Professor-Astronomer I. F. Polak, Professor of Physics A. F. Golubentseva, Professor, graduate of the Faculty of Physics A. M. Chaykina . A special essay reflects the outstanding events that took place in the Great Physical Auditorium of the University of Saratov . For teachers, graduate students and university students.