Another Quantum of Solstice...

Rutherford and Bohr

[this story continues in part from here.]

Ernest Rutherford discovered the atom's very kernel, the nucleus, but his tiny solar system model of the atom failed. It failed because it had a fatal flaw according to classical electromagnetic theory: Viewed side-on in the plane of the ecliptic, the orbiting electron oscillates charge from side to side and should behave like a miniature transmitter, broadcasting electromagnetic energy like a Marconi transmitter. Giving off energy, bit-by-bit, the electron should spiral into the nucleus. Rutherford never explained that away.

The Importance of Being Near Ernest

Luckily, Rutherford confided his 1909 experiments to young Niels Bohr prior to publishing them. Rutherford had invited Bohr to Manchester to study physics after a brief (and apparently unsuccessful) stint at Cambridge. Inspired,* Bohr spent the summer of 1910 and the subsequent spring (taking time off to marry and to honeymoon), devising his own theory which he published in 1913 (two years after Rutherford finally published his planetary model in 1911).

Bohr got around Rutherford's electron death spiral problem by postulating that it didn't happen! That may sound audacious and even glib, but he overcame "illogical leaps" by solving a bigger mystery which had puzzled generations of scientists: he explained the long-known but little-understood signature hydrogen lines observed in the spectra of stars (recall that stars are mostly hydrogen). According to Bohr, the lines represented quantum leaps in units of energy. He did the math for the hydrogen atom to prove it. The simplistic hope that atoms and the universe were fundamentally similar -- the too small to be seen and the too big to be noticed were whirling masses in motion or "turtles all the way down" -- shone briefly.

According to Bohr's new 1913 theory, electrons encircled a nucleus, but only in stable, fixed-distance orbits (shades of Bode's earlier but discredited planetary law?) but without the continuous death spiral energy radiation. Bohr called his quantized orbits "stationary orbits" (whence my title). A quantum of solstice or standing still.

Electrons in Bohr's stationary orbits still gained or lost energy -- but only by jumping from one orbit to a bigger orbit and vice verse. That was revolutionary. Bohr's math worked out too and depended on Planck's constant which was only 13 years old then.

Planck quantized radiation and Bohr quantized matter--viz, electrons. Scientists struggled in subsequent years with the question of whether electrons were waves or particles and whether light rays were waves or particles. They worried about the meanings of such apparent dichotomies until they gradually realized that they were fighting about language and not about science.
 _______________
*Inspired is an understatement

****

My inspiration for the "Quantum of Solstice" is here at Victoria's old blog, to whom I dedicate this blog post.

Nickel and Diming US 'Til Death Do US Part

1913 Indian Head (Buffalo) Nickel, designed by James Earle Fraser.

1913 was an odd year, seeing the introduction of the Buffalo (Indian Head) nickel, and also the ratification of the 16th Amendment which introduced the permanent Federal Income Tax.

I recently finished reading a scholarly paper about the history of the 16th Amendment called "The Ratification Of The Federal Income Tax Amendment" by John D. Buenker.  There's a PDF copy here. The article is old (1980) but still relevant, especially in view of the subsequent Reagan Revolution and the more recent Obama Revanche. I took note of quite a few themes and arguments, because they never seem to go out of style. I want to write something further on this topic and this is just sort of a place keeper.

Ligation Was His Religion But His Love Was Platonic

A relatively obscure Swiss chemist named Alfred Werner won the Chemistry Nobel Prize in 1913. In retrospect, it was ironic (but coincidental) that someone from a neutral country won for ostensibly organizing things, a year before things really started to fall apart in Europe. Stockholm did the same thing the following year when they awarded T.W. Richards, an American, the prize in the midst of the Great War. They even gave the prize to a German, Richard Willstätter, in 1915 for his seminal work on chlorophyll (which happens to an example of a magnesium-ligand complex: link). Then the Nobel Prize was suspended for two years until 1918 when another German, Fritz Haber won it, despite his innovations in poison gas warfare. But back to Alfred Werner.  What did he do that so moved the committee?

For starters, he reorganized the Periodic Table and he taught generations of chemists how to think about it. Secondly, he got chemists to think beyond carbon and the tetrahedron--to octahedra and polyhedra. What le Bel and van 't Hoff did for carbon, Werner did for everything else. He introduced the general notion of the coordination complex, merging the novel concept of a central atom surrounded and ligated with ligands arrayed like classical Platonic solids. Something new and something old.

An elderly professor once showed me the carefully preserved remnants of Alfred Werner's laboratories at the University of Zurich. They're stored under lock and key these days, partly out of lack of space, partly out of lack of interest. And yet Werner's long forgotten contributions changed chemistry as much as any of his peers.

Just A Thought...

cuban bob wrote: Our local NPR station had a big story on Monday about how this is killing the funding for highway maintenance.

This reminded me of Ken Burns' "Prohibition" when he taught how a potential loss in federal tax on alcohol was a major deterrent for enacting Prohibition--the Feds wondered how they could recoup losses if such a national prohibition law were to pass. But the 16th Amendment (Federal Income Tax) nicely solved that in 1913 and paved the way for the subsequent Volstead Act.

Beware any national energy tax to offset declining fuel tax revenues--it could be a prelude to a stricter prohibition on hydrocarbons.
________________
crossposted at Althouse