Friedrich Wilhelm Ostwald was a Baltic German chemist and philosopher. Ostwald is credited with being one of the founders of the field of physical chemistry, with Jacobus Henricus van 't Hoff, Walther Nernst, and Svante Arrhenius.
He received the Nobel Prize in Chemistry in 1909 for his scientific contributions to the fields of catalysis, chemical equilibria and reaction velocities.
Ostwald c. 1883
Jacobus van 't Hoff (left) and Wilhelm Ostwald
Liesegang rings at Saginaw Hill, Arizona, USA
Ostwald viscometer
Physical chemistry is the study of macroscopic and microscopic phenomena in chemical systems in terms of the principles, practices, and concepts of physics such as motion, energy, force, time, thermodynamics, quantum chemistry, statistical mechanics, analytical dynamics and chemical equilibria.
Between the flame and the flower is aerogel, whose synthesis has been aided greatly by physical chemistry.
Fragment of M. Lomonosov's manuscript 'Physical Chemistry' (1752)