 # Boltzmann constant – Putting it in perspective in Physics – Part 1

In this series, we will begin with the famous Boltzmann constant, and try to put it in perspective. That is, its most basic form, original usage, significance, where else it is used, who were the people involved, some chronology, historical perspective, etc. We’ll try to do this in small pieces, bite-size, non-overwhelming. This article is only the overview of what we’ll go into a little deeper in following articles. So we will start with the Boltzmann constant. And its basic form in the Ideal Gas Equation.We’ll look at its relation with the Universal Gas Constant and Avogadro’s number. We’ll look at these 2 terms a bit too. Then we will take a look at where else this term is used. Natural candidates are terms where the name Boltzmann is used.That is:

• Boltzmann distribution
• Boltzmann’s (Differential) Equation
• Maxwell-Boltzmann distribution
• Maxwell-Boltzmann statistics
• Stefan-Boltzmann law

As it turns out, all of the above do use the Boltzmann constant.

Boltzmann and his constant (the constant named after him) mark an era in the development of physical science, of the inclusion of a statistical/probability approach. This was in line with the advent of investigation of microscopic matter as opposed to only macroscopic / deterministic/ Newtonian physics previously.

This led to the development of Statistical mechanics and its corresponding mathematical frameworks (Statistical ensemble – mathematical physics)

With his work, Boltzmann was instrumental for getting acceptance of matter as comprising of atoms and molecules.

This led to the led to the development of Kinetic theory–a key branch of Thermodynamics.

An early breakthrough in this field that helped build its foundations was Brownian Motion, involving Einstein and Perrin.

Statistical mechanics (its branch – Particle statistics) is used in Quantum Physics too, to describe the states of matter.

e.g.-

Bose-Einstein Statistics

Fermi-Dirac Statistics

In this context, some of the key scientists to look at are (intentionally mentioning their life-cycles to appreciate the sequence) :

• James Clerk Maxwell (13 June 1831 – 5 November 1879)
• Ludwig Eduard Boltzmann (February 20, 1844 – September 5, 1906)
• Josiah Willard Gibbs (February 11, 1839 – April 28, 1903)
• Max Karl Ernst Ludwig Planck (April 23, 1858 – October 4, 1947)
• Albert Einstein (14 March 1879 – 18 April 1955)
• Jean Baptiste Perrin (30 September 1870 – 17 April 1942)