Thursday, 16 July 2009

Another New "Old" Term


Adjusting some notes in my web page the other day, I was editing a page with a note on the Electron.
Here is some of it:

Our solar system is often called heliocentric because the sun is at the center. The purpose of that sentence was not to teach you science, but to point out the three different word roots that are used to refer to the star that gives life to our planet, sun, helios, and sol.
In ancient Greek myths Hyperion was the god of the sun, but eventually this became more associated with his son, helios. An eclipse in India in 1868 offered an opportunity to do something never before done, pass light from the Sun's atmosphere through a spectroscope. When light passes through a spectroscope it breaks into bands of unique colors that represent pure elements. One color was at a position never found on Earth. Assuming that the element only occured in the Sun, Astronomer Norman Lockyer named it Helium, "sun element". Later it was found on earth, but the name stuck.

When the Romans conquered the Greeks, their fascination with the Greek culture led to retaining many of the same myths, with the major characters replaced with a related Roman god. The Roman god associated with the sun was Sol, and thus we get words like solar system, parasol , and solarium (sun room). The para in parasol is not the same as the para in parabola and parallel, but comes from the Latin parare, which means to prepare. A parasol is thus preparation for the sun.

The word sun, itself, may come from the same Indo-European root that gave us sol, or perhaps there is an old Norse or Tutonic god out there I haven't found yet. However it started, it made its way from the Germanic into the Middle English as sunne to become our sun of today.

Another Greek word for our closest star was elector, which meant something loosely like "bringer of light". Things that reminded them of the brillance or color of the sun, such as amber, were called electrum. Even the early Greeks were aware of the effects of magnets and recoginzed that, when rubbed, amber acted like a magnet to some small light objects. In 1600 when English Scientist William Gilbert wrote De Magnete Magneticisque Corporibus, the similarity of the behavior of magnets to the effects of amber inspired him to create the word electricity from the Greek word for amber. The unit of magnetomotive force in the CGS system is called the Gilbert in his honor. Gilbert is buried in St. Johns College Chapel in Cambridge, Uk.

By now you've probably figured out that the name for the electron also is related. When JJ Thompson discovered the particle we now call the electron while studying the mysterious cathode rays in tubes, he called them corpuscles. The Word, Electron had been coined earlier by G. Johnstone Stoney in 1891. Stoney used the word to denote the unit of charge found in experiments that passed electric current through chemicals. He had written about the unit of charge as early as 1874, making him one of (if not the) first to recognize that, in his words, "For each Chemical bond which is ruptured within an electrolyte a certain quantity of electricity traverses the electrolyte, which is the same in all cases." He first referred to the unit quantity as E1.

In the same sense the term was used by Joseph Larmor, J.J. Thomson's Cambridge classmate. Larmor devised a theory of the electron that described it as a structure in the ether . But Larmor's theory did not describe the electron as a part of the atom. When the Irish physicist George Francis FitzGerald suggested in 1897 that Thomson's corpuscles were really "free electrons," he was actually disagreeing with Thomson's hypotheses. FitzGerald had in mind the kind of "electron" described by Larmor's theory. The idea did not stick, but the name did.

I was reading an old Philosophical Magazine (October, 1894) article by Stoney about the creation of the unit and the term, when I was struck by an unusual notation I had never seen before. He describes the unit of charge of the electron as three eleventhets of the C.G.S electrostatic unit of quantity. This he illustrates to be 3 x 10 -11.
After a little research, I found another article by Stoney, in the November 1899 issue of the same magazine which he had presenter earlier to The Scientific Proceedings of the Royal Dublin Society. In the article he defines several terms which, I assume, he is the creator of (please correct me if you have information on this).

If any of these terms below are still in use by someone, I would appreciate information about the nature of that use.



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