Born on Jan. 2, 1822, in Köslin, Pomerania, R. J. E. Clausius was the sixth son of the 18 children of the Reverend C. E. G. Clausius, a Lutheran pastor and councilor of the Royal Government School Board in Köslin. Young Clausius received much of his primary and secondary education in the private school which his father established in Uckermünde. After graduating from the gymnasium in Stettin, Clausius enrolled at the University of Berlin, and in 1844 he obtained his teacher's certificate

Rudolf Julius Emanuel Clausius (January 2, 1822 – August 24, 1888), was a German physicist and mathematician who was among the first to clearly formulate the fundamental principles of thermodynamics. He also placed the kinetic theory of gases on a firmer footing than his predecessors and coined the word entropy to describe an important thermodynamic quantity.

Clausius was born in Köslin in the Province of Pomerania, the son of the Rev. C.E.G. Clausius, a clergyman and educator. He started his education at a school established by his father. After a few years, he went to the Gymnasium in Stettin. Clausius entered the University of Berlin in 1844, where he studied Mathematics and Physics with, among others, Heinrich Magnus, Johann Dirichlet, and Jakob Steiner. He also studied history with Leopold von Ranke. He graduated in 1844, and earned a doctorate from the University of Halle in 1847, with a dissertation on the optical effects of the Earth's atmosphere.
Clausius's doctoral thesis on the refraction of light proposed that the blue sky observed during the day, and various shades of red at sunrise and sunset (among other phenomena), were due to the reflection and refraction of light. Later, Lord Rayleigh would show that the color of the sky was produced by the scattering of light. Nonetheless, Clausius used a far more mathematical approach than his predecessors