## Who Was James Clerk Maxwell?

Pioneer in Electricity and Magnetism

We are paying homage to the Scottish born mathematical physicist and electrical genius named James Clerk Maxwell. While James Maxwell isn't as widely known as let's say Einstein or Tesla or even Faraday, each one of those innovators in their own right pay homage, in one way or another, to Maxwell. Alfred Einstein expressed great admiration for Maxwell's achievements in Physics in his 1921 Nobel Prize in Physics address, which he titled "Maxwell's Influence on the Evolution of the Idea of Physical Reality". In that paper Einstein explains how Maxwell, and to lesser degree Faraday and Hertz, re-imagined how we explain the physical reality around us. Maxwell explained for the first time how electric and magnetic fields are inter-dependent. That they are directly related to light itself. To quote Einstein, "He showed that the whole of what was then known about light and electromagnetic phenomena was expressed in his well-known double system of differential equations, in which the electric and the magnetic fields appear as the dependent variables." Of course he was referring to Maxwell's Equations, which represent one of the most elegant and concise ways to explain the fundamentals of electricity and magnetism.

Before Maxwell, and from the time of Newton, the whole of physical reality was explained in mechanical terms and concepts. Maxwell extrapolated the concept of magnetic field theory, and developed his now famous equations that we know simply as Maxwell's Equations. These four eloquent equations formulate the theory of electromagnetic radiation, which bring together for the first time electricity, magnetism and light as manifestations of the same physical phenomenon.

Taking a basic experiment, Maxwell demonstrated the magnetic field surrounding a bar magnet by sprinkling iron filings on a piece of paper suspended over the magnet. The iron flecks oriented themselves as if to map out the polar forces of the bar magnet. In 1862, Maxwell calculated the speed of the propagation of this electromagnetic field, and to his surprise, it was essentially the same as the speed of light. This led him to conclude that light travels in waves and was part of the electromagnetic phenomenon. This led to what we now know as the Electromagnetic Spectrum, with its increasing wavelengths from gamma rays to radio waves. This is a cornerstone of modern science.

Maxwell introduced the use of vector fields in his ground-breaking two volume publication "A Treatise on Electricity and Magnetism" (1873). In deference to Maxwell, we still use his labels when writing electromagnetic equations:

A (vector potential), B (magnetic induction), C (electric current), D (displacement), E (electric field - Maxwell's electromotive intensity), F (mechanical force), H (magnetic field - Maxwell's magnetic force)

- He was born on June 13, 1831 in Edinburgh, Scotland.
- In 1847, at the age of 16, Maxwell attended the University of Edinburgh. He studied Mathematics, Natural Philosophy (Physics) and Logic.
- In 1856, Maxwell published simple mathematical equations that could express the behaviour of electric fields and magnetic fields and how they interrelated. This came about when Maxwell provided the mathematical formulas for Michael Faraday's theories of electric and magnetic lines of force.
- In 1857, Maxwell embarked upon the study of the motion of Saturn's Rings. He showed that their stability could only be achieved if the rings were made up of many small solid particles. This was confirmed in the 1970's with the Voyager spacecraft flybys.
- In 1860, Maxwell was appointed the chair of Natural Philosophy at King's College in London.
- In 1862, Maxwell calculated that the speed of an electromagnetic field is approximately the same as the speed of light. He proposed that light itself is therefore an electromagnetic phenomenon.
- In 1865, he left King's College to work at his estate called Glenlair in south-eastern Scotland.
- In 1866, Maxwell worked on the kinetic theory of gases. This work demonstrated that temperature and heat involved only molecular movement.
- In 1871, he became the first Cavendish Professor of Physics at Cambridge.
- In 1873, Maxwell published his influential work 'A Treatise on Electricity and Magnetism'. His four partial differential equations, now known as Maxwell's equations, are one of the great achievements of 19th century mathematics.
- In 1879, he became progressively ill and returned to Glenlair.
- On November 5, 1879 Maxwell died in Cambridge, England.