Electrons - A Cautionary Tale


In 1897 J. J. Thomson conducted a series of experiments that yielded the first subatomic particle, the electron,

and he spent the remainder of his career exploring its properties.

This was a time of great excitement for Physicists - the Curries were busy in France irradiating themselves and everyone and their dog brimmed with speculation on the nature and structure of the Atom, including Thomson himself.  He decided that the best thing to do with his electrons was to embed  them in a field of positive charge, an idea later dubbed The Plum Pudding Theory of the Atom.

What was odd about Thomson's model was that it was made of whole cloth, without experimental evidence or, even, logic behind it.  This was very peculiar behavior for a scientist, falling well outside of the Scientific Method with its Prohibition of going beyond your data.

Yet Thomson was convinced he'd cracked the Atom.

Turns out that Thomson was taking a page from an academically based branch of mathematics that had been gaining ground since mid-century and whose practitioners called themselves theoretical physicists.  Unconstrained by the Scientific Method, these mathematicians felt free to speculate as wildly as they liked, just as long as the number agreed.  This was the attitude that Thomson was mimicking and it served him well, elevating him to King of the Atom.

Time passed and then, in 1909, another experimental physicist, Ernst Rutherford, decided to see what what would happen if you bombarded various materials with what were, at the time, called Alpha particles.  One of the materials he choose was gold foil and the result would become the atom as we know it.  Almost all of the alpha particles flew straight through the foil but the ones that didn't bounced back in coherent patterns, suggesting that they were bouncing off a very small positive charge.  That charge would become our atomic nucleus.

Rutherford himself stuck with the data, presenting his findings in 1911 as a model of small, positively charged centers surrounded by a lot of space. Electrons were, no doubt, part of the mix but what part would have to wait for more data.  A few years later, in 1919, Rutherford was able to establish that those centers were, indeed, particles and coined the term, Proton.  But, by then, the world of Physics had long since passed him by, thanks to one of his students: Neils Bohr.

Bohr, a mathematician, didn't hesitate to assume that electrons orbited Rutherford's 'centers' but there was a problem: according to Newtonian Physics, the orbit of a single electron around a single nuclei should decay and crash into the nuclei.  Bohr presented this problem to Rutherford, Rutherford found the problem disturbing but back-burnered it because the relationship between 'centers' and electrons had yet to be establish experimentally.

Bohr, while deferring to Rutherford, didn't.  He returned to his hometown, Copenhagen, and puzzled over the problem until, in a flash of inspiration, he decided to try a constant; specifically, Planck's Constant.  This did the trick, electron orbits around single nuclei levels stabilized, just as long as they were multiples of that constant.

A consequence of this solution was power levels: if you added or subtracted energy from the electron in multiples of Planck's Constant, it would jump from higher and lower orbits.  There was just one little problem with these jumps, they were physically impossible.

In order for Bohr's orbits to work, they had to be invariable; the slightest waver would send the electron crashing into its nucleus.  So if the electron tried to move to a higher or lower orbit physically, boom!, straight into the nucleus.

Bohr's solution was simple; if electrons couldn't jump physically, they'd do it by magic: dematerializing from one orbit and rematerializing in another with no physical process involved.  This is the Quantum Leap and  Bohr unveiled this version of Rutherford's model  in 1913.  Magically, all of his fellow mathematicians bought it.  The Atom was solved, Bohr got all the credit and Rutherford was left out in the cold.

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What Bohr really demonstrated was why the Method discouraged going beyond your data: in 1913, all that was really known about atoms was Rutherford's positively charged 'centers' and the vast space between them.  Bohr's electron orbits were pure speculation, impossibly rigid and based on the assumption that electrons orbit bachelor ions.

Bohr had jumped the gun, big time.

In reality, electrons only become important when ions decide to start making molecules - they're the glue holding the new structures together and, since each electron 'orbits' two ions, there's no danger of it crashing into either.  The attraction of one takes over before the electron's orbit can decay with the other.

But in the Wild, single nuclei, bachelors, lone wolves, stags, while amenable to one-night stands, aren't interest in anything permanent.  Electrons can wiz by, like bus-ride fantasies, slingshot like casual encounters or crash and burn like Jersey Shore trysts; to the ion, it's all the same.  Except the Jersey Shore trysts; they result in Neutrons if one of the partners is a hydrogen ion.

Bohr never watched Jersey Shore and had no idea what a neutron was anyway.  That little bit of news wouldn't break for another 20 years.

In fact, Bohr had no idea what any elemental ion, larger than hydrogen, was in terms of structure or dynamics.  All he knew was numbers.

Bohr was also either ignoring or was unaware of a way electrons could orbit ions without crashing into them: synchronous orbits which, effectively, tether the electron to the ion.  In this case, the ion has to be rotating and the electron has to match the speed of that rotation but, once tethered, the electron can slid up down an imaginary, knotted little string, each knot a power level, all in a purely physical, Newtonian process.  No need for Quantum Leaps.

So, bathed in ignorance, Bohr solved a problem that wasn't a problem with impossibly rigid orbits of electrons that had to magically dematerialize and rematerialize to change power levels and his peers not only bought the whole thing, they built a brand new branch of physics on it: Quantum Theory.

You gotta wonder, what the hell is really going on here?

The answer is, partially, a peculiarly intense,Teutonic yearning for stasis, an unintended consequence of a Neolithic farmer's decision to plant his crops in rows.
















































































































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