The Russian physicist and physical chemist Nikolai Nikolaevich Semenov (1896-1986) is famous for his experiments explaining chemical reactions by means of the mechanism of chain reactions.

Nikolai Semenov was born on April 15, 1896, in Saratov. He displayed a keen interest in the physical sciences by the time he was 16 and in 1913 entered the physics and mathematics department of the University of St. Petersburg (later Petrograd and now Leningrad). At the age of 20 he published his first paper on the collision of molecules and electrons. In 1917 he ended his studies at the University of Petrograd, obtained a position as physicist in the Siberian University of Tomsk and later, in 1920, returned to work for the next 11 years at the Petrograd (in 1924 Leningrad) Institute of Physics and Technology.

In 1928 Semenov became a professor at the Leningrad Polytechnical Institute and organized its physics and mathematics department. Three years later he was appointed scientific...