James Maxwell
and
His Discoveries
“From a long view of the history of mankind – seen from, say, ten thousand years from now – there can be little doubt that the most significant event of the nineteenth century will be judged as Maxwell’s discovery of the laws of electrodynamics.” — Richard Feynman
James Maxwell was a Cambridge educated mathematical physicist from Scotland. He collaborated with Michael Faraday to unravel some of the mysteries of physics. In that process, they unified, what then considered to be, three different phenomena of physics – electricity, magnetism, and light.
As you may know, Faraday was the first scientist to propose the ideas of electromagnetic field and magnetic induction. Maxwell packaged these ideas in the form of sophisticated mathematical equations. Their groundbreaking work and, in particular, the prediction of electromagnetic waves changed the world. In addition, it led to many other triumphs in physics in the twentieth century including the Special Theory of Relativity by Albert Einstein.
Maxwell's Childhood
James Maxwell was born in Edinburgh, Scotland on June 13, 1831. Soon, he showed himself a remarkable child by asking questions about things around him. Anything that moved, shone, or made noise made him extremely curious. Invariably, his curiosity was followed by many questions which adults were hardly able to answer.
At the age of fourteen, Maxwell published his first paper. The paper was on how to draw complex curves easily using simple tools such as pins, a piece of string, and a pencil. Someone had to read out that paper to the Royal Society of Edinburg on his behalf because he was too young to do himself.
Maxwell's Discoveries
Though he is popular for his discovery of the laws of electromagnetism, he made great contributions in other areas of physics such as kinetic theory of gases, color vision, and Saturn’s rings. Especially, he partnered with Ludwig Boltzmann in developing groundbreaking theories – Maxwell-Boltzmann distribution of molecular energies – in kinetic theory of gases.
Electromagnetic Theory
Having been inspired by Faraday’s lines of force idea, after reading the books of Faraday and Ampere, Maxwell was convinced that Faraday’s theory of lines of force must be right. He realized that his task was to find a way to express Faraday’s ideas in mathematical language. As Faraday’s ideas lacked mathematical explanations, he intended to come up with a mathematical theory in support of Faraday’s lines force.
After 18 years of persistent work, from 1855 to 1873, and after publishing several papers on this topic, Maxwell published the book “Treatise on Electricity and Magnetism” in 1873. He explained all the observed phenomena of electricity and magnetism mathematically using twenty equations. The theory also predicted the existence of electromagnetic waves.
Maxwell’s theory was too complicated to understand. He had used a complicated mathematical tool called quaternion. In addition, it required paradigm shift in thinking. Therefore, the fellow scientists of his time were baffled and ignored his theory. It needed another genius, Oliver Heaviside of London, to bring out the meaning of Maxwell’s mathematics.
Heaviside, in 1882, developed his own mathematical tool – vector algebra – and converted Maxwell’s twenty equations into four simple equations, in 1885, which are easy to grasp.
These four (Maxwell’s) electromagnetic equations explain diverse range of phenomena.
Maxwell's Equations
Here are Maxwell’s four electromagnetic equations.
We will have a detailed discussion on these equations in a separate post.
Maxwell’s electromagnetic theory demonstrated a profound idea that mechanical means were not good enough to express nature’s working. Even our senses cannot feel every nature’s function. We can only mathematically express nature’s workings. This idea required a paradigm shift in thinking.
Electromagnetic theory of Maxwell paved the way for great discoveries in physics such as Einstein’s Special Theory of Relativity, Feynman’s Quantum Electrodynamics, and Standard Model in particle physics.
Impact of His Discovery
Faraday-Maxwell collaboration resulted in the unification of electricity, magnetism, and light, and also it predicted the existence of electromagnetic waves. Maxwell’s theory concluded that light must be electromagnetic in nature.
Later, Heinrich Hertz of Germany, in 1888, successfully produced and detected electromagnetic waves in free space.
In the beginning of 20th century, the young Italian Guglielmo Marconi had seen the commercial potential of radio telegraphy using electromagnetic waves. He founded his own company, and successfully transmitted the first wireless message across the Atlantic in 1901 from Poldhu, Cornwall, UK. A kite-borne antenna instantly received that message in Newfoundland, Canada.
Today, we take all the technologies which make use of electromagnetic waves for granted. Can we imagine a world where there are no cell phones, no radios, no radar, no televisions and no wireless communication? Obviously, Maxwell did not recognize the importance of his discoveries.
Other Discoveries
Experiments with colors:
James Maxwell demonstrated that you really could get any color you wanted by mixing red, green, and blue in the right proportions. We use this principle in our color televisions today.
Kinetic theory of Gases:
Maxwell was the pioneer in using statistics to solve the problem related to gases. He showed that a bell curve could represent the distribution of speed of molecules. Maxwell had opened the door to a great new area of scientific knowledge – in particular to a proper understanding of thermodynamics, statistical mechanics, and to the use of probability distributions in quantum mechanics.
Maxwell’s work on kinetic theory of gases inspired Ludwig Boltzmann so much that he spent most of his career developing the subject further. Each got inspired by other’s work and would counter with a further extension of other’s theory. They were, in effect, a magnificent partnership that their names are jointly in “Maxwell-Boltzmann distribution of molecular energies” theory.
Saturn’s Rings:
Like anyone, Saturn’s rings fascinated Maxwell. No one knew, at that time, what these rings were made of. He participated in a contest where the question was: under what conditions would the rings be stable if they were solid, fluid or composed of many separate pieces of matter?
Maxwell managed to prove mathematically that solid rings would inevitably break up, and that the same would happen to fluid ones as the tidal waves grew bigger and bigger.
He had thus shown that although rings appear to be continuous, they must consist of many separate bodies orbiting independently – exactly the structure we have now seen on fly-by pictures from the Voyager and Cassini space probes.
True Scientists
Maxwell and Faraday were perfect embodiment of a true scientist. They were curious, objective, persistent, and without any pride. Their collaboration resulted in a theory that became the foundation for great new discoveries in physics in the twentieth century.
Can you imagine a world without the wireless technology today? Their discoveries made possible a vast array of technologies that completely changed our lives. No doubt, we must be thankful to both Maxwell and Faraday for their magnificent work.
Reference:
- Faraday, Maxwell and the electromagnetic field. How two men revolutionized Physics by Nancy Forbes and Basil Mahon