Remembering Physicist James Prescott Joule
Renowned physicist James Prescott Joule passed away in 1889 at age 71. James was an English physicist who conducted work in thermodynamics and formulated the relationship between mechanical work and heat generation, known today as “Joule’s law” or the “first law of thermodynamics.” This is a statement of the conservation energy usually expressed in terms of the energy change in a system being equal to the difference in the heat supplied and the work done.
Importance of Thermodynamics
James prepared the way for our understanding of the concept of energy and the interconversion of different forms of energy, including mechanical, electrical, and thermal energy.
I want to remain with the laws of thermodynamics as the importance of the 2nd law was beautifully illustrated by the colossal “Giant” Arthur Eddington (1882-44), the Trinity College Physicist (Einstein’s (1879-55) champion), who was the first to demonstrate the superiority of Einstein’s General Theory of Relativity over Newton’s (1643-27) inverse square law by measuring the bending of light by a star and for its prediction of the precession of the perihelion of Mercury. These two epoch-making tests relegated Newton’s work to being only a “good” approximation to our understanding of gravity and ushered in the way for Relativity to take centre stage. Of course, one must not be too quick to dismantle Newton as the inverse square law got us to the moon and back.
Legacy of Eddington
Remaining with Eddington, he said the following of the 2nd law of Thermodynamics and remains one of my favourite quotes in Physics:
“The law that entropy always increases holds, I think, the supreme position among the laws of Nature. If someone points out to you that your pet theory of the universe disagrees with Maxwell’s equations – then so much the worse for Maxwell’s equations if it is found to be contradicted by observation – well, these experimentalists do bungle things sometimes. But if your theory is against the Second Law of Thermodynamics, I can give you no hope; there is nothing for it but to collapse in deepest humiliation.”
A. Eddington.
Returning to Joule, his contributions significantly advanced the field of thermodynamics and impacted the scientific understanding of energy and heat. He proposed a kinetic theory of heat but considered it a form of rotational rather than translational kinetic energy.
Conclusion
Scholars say that James presented his ideas to an elite triad of “Giants” George Gabriel Stokes (1819-03), Michael Faraday (1791-67), and William Thomson (1824-07), later becoming Lord Kelvin. That must have been quite scary! I will end this discussion by illustrating how even the greats of the past can make monumental errors, as Kelvin predicted the sun’s age to be 20 million years, and we know today that it is over 5 billion years old.
I have run out of space again until next time.
