1913: Atom - The book of science

Atom
Benefits and liabilities
Guessing theory
Commentary

Atom

J. J. Thomson’s model of the atom—a cloud
of electrons like plums in a positively charged pudding—
didn’t explain why a few random alpha particles,
shot into gold foil—when most passed right through—
bounced straight back. Ernest Rutherford realized
that the atom had a small and dense center, its nucleus—
with a diameter less than one three-thousandth of the atom’s diameter,
but over ninety-nine point ninety-four percent of the atom’s mass—
which, being positively charged, keeps its electrons
orbiting around it, leading Niels Bohr—in explaining
the pattern of spectral emissions of helium—to say
electrons are confined to concentric spherical shells
around the nucleus, and for an electron to jump
between shells it must absorb or emit the definite amount
of energy associated with the difference of energies between the shells,
which explains why atoms emit light in sharply defined spectral lines.

Benefits and liabilities

Atoms plus an understanding of the periodic table
gives us chemistry. Atoms plus magnets to move its electrons
gives us electricity and electronics. Atoms plus the forces
in the nucleus give us the atom bomb. If we understand the parts
and how they are put together, then we can take them apart
and put them back together in useful ways. Some of these operations
require energy, and some release energy. The goal is to control
the benefits and to limit the risks, which for most of the effects
induces denial whose strength is equal to the anticipated power.

Guessing theory

My first-order approximation
is a wild and crazy guess.
My second-order approximation tries only
to make the guess seem less crazy.
On further analysis, in some restrictive
sense, it might be somewhat true,
but if it’s fundamentally flawed
then I can see how to change it.
I run my third-order approximation
through a battery of hypothetical scenarios,
each of which may suggest a qualification,
a refinement, or an additional guess.
Pretty soon, what begins as a form of fun
becomes totally unwieldy, like reality.

There have been other models of the atom, including the cubical atom model, which explained bonding between atoms by sharing electrons at corners, and the Saturnian model, where electrons rotate around a positive nucleus like the rings of Saturn. The Bohr model also was not the last, being superceded by the atomic orbital or wave mechanics model, in which the orbits of the electrons are described by the probability equations of quantum theory.