Ludwig Boltzmann: The Father of Statistical Mechanics

Ludwig Edward Boltzmann is one of the elite theoretical physicists of the later nineteenth century. An advocate for the existence of atoms, he is a known face for his role in the development of statistical mechanics. He gave statistical explanation of the second law of thermodynamics and contributed significantly towards kinetic theory of gases.

Ludwig Boltzmann
Ludwig Boltzmann
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Early life and Education:

Ludwig was born in Vienna on February 20, 1844 to Ludwig Eduard Boltzmann and Ludwig Georg Boltzmann. His father was a tax official. Initially taught by a private tutor, he started attending the local gymnasium later. Here, he showed great aptitude in mathematics and science. At the age of 19,Boltzmann enrolled at the University of Vienna. Here, he studied mathematics and physics, eventually earning his PhD degree three years later in 1866. Boltzmann's doctorate thesis focused on the kinetic theory of gases.

Scientific work:

Boltzmann's first significant contribution to physics was the generalization of James Clerk Maxwell's distribution of velocities and energies for a sample of gaseous atoms. He provided the explanation of the second law of thermodynamics in the early 1870s on the basis of the atomic theory of matter. The famous Boltzmann entropy formula was formulated by him between 1872 and 1875 and Planck put it into its current form in 1900.

Boltzmann Entropy Formula

Boltzmann demonstrated that the second law can be interpreted by blending the laws of mechanics, applied to the motions of the atoms, with the theory of probability. He made detailed calculations in the kinetic theory of gases. Ludwig Boltzmann was also one of the first people to understand the significance of James Clerk Maxwell‘s theory of electromagnetism. He even wrote a two-volume treatise on it. Boltzmann also worked on a derivation for black-body radiation based on the Stefan’s law. This was later termed as “a true pearl of theoretical physics” by Hendrik Antoon Lorentz. Boltzmann is also referred to as one of the founders of quantum mechanics as he suggested about the discreteness of energy levels in a physical system.

Also Read: What do Maxwell's equations really mean?

Teaching career:

Ludwig Boltzmann obtained his first professorship in 1869 as professor of mathematical physics at the University of Graz. During his lifetime, he taught mathematics, experimental physics and theoretical physics at several universities, but theoretical physics was his main passion. According to many of his students, Boltzmann was an outstanding teacher, and his lectures were often a treat to attend. He displayed a compatible attitude toward students and their learning. This kind of teaching methodology was something rather rare among Austrian and German professors at that time.

Importance of Boltzmann's Scientific ideas and contributions :

Kinetic theory is an important instrument in the study of dilute gases. It is widely applicable in systems where particles have large mean free path length and collisions are rare. Hence, it is employed while studying the behavior of stellar clusters and interstellar gases. Kinetic theory is also important in study of non relativistic plasmas.

The statistical explanation of second law as given by Boltzmann works as the foundation of Statistical mechanics. Boltzmann's principle gives an expression for the entropy of a system in thermodynamic equilibrium. Entropy is itself a thermodynamic property that acts as a bridge between the macroscopic and the microscopic properties of the system. Thus, Boltzmann's entropy formula plays an important role in connecting two important branches of physics: statistical mechanics and thermodynamics.

Also read: What does the Boltzmann equation really mean?

Depression and Suicide :

No doubt, Boltzmann's work and idea are of great importance in nature. Still, Boltzmann's work always met with mixed reactions during his lifetime, and continue to do so even today. He was firm defender of the atomic view of matter. However, at that time, influential authors like Mach and Ostwald, disapproved of this view. His ideas faced serious criticism. People did not believe in the physical reality of molecules nor in Boltzmann’s treatment of them. He suffered from an alternation of depressed moods. Attacks on his work continued. He started feeling that all his life's work is going to collapse.

Eventually, going through severe depression, On September 5, 1906 Boltzmann committed suicide. He was on a holiday with his wife and daughter. There, he hanged himself while his wife and daughter were swimming. But, see the irony of nature! Just a few weeks after he committed suicide, his work was experimentally verified!
Boltzmann's tombstone bears the inscription of his famous Boltzmann's entropy formula, as a tribute to the genius.

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