> It's a phenomenon that has something to do with electricity, magnetism, 
> waves and particles, but nobody really understands what exactly. ;-)
>
> Specifically, light is an electromagnetic wave (or is it a subatomic 
> particle?) in a particular frequency range (or is that particle energy?) 
> that registers in our eyes due to the chemical transformations it induces 
> in certain protein groups.

E=MC^2
All matter is both mass and energy.
Photons are "packets" of energy that fluxuate between
electical potential and magnetic potential at a certain frequency,
a.k.a. an electromagnetic wave.
They have more energy than an electron.

> However, it's really damn unusual for a material's electrical or magnetic 
> properties to have any bearing at all on its optical properties.

This is a common misconception.
The color of normal objects IS an electrical property,
it is the variation in electrical conductivity at optical frequencies.

> * Impure water is an excellent conductor, while pure water is a very good 
> insulator. Yet both substances have almost identical optical properties.

Resistance in materials varies by frequency.
Both salt-water and pure water are conductive at optical frequencies.

> * Iron is highly magnetic, while aluminium isn't. Good luck telling the 
> two metals apart by their appearence!
>
> * Electricity does not, under any remotely "normal" conditions, produce 
> light or affect it in any way. (E.g., you can't bend light using 
> electricity.) The same goes for magnetism.

Because photons are in high frequency flux, they have both positive
and negative charge, or no DC charge (depending on
how you look at it).

> Sure, theoretically they're related. But it's not something you see in the 
> real world very often. ;-)
>
> (I still can't figure out why you can use an oscilator to make radio 
> waves, but not light rays...)

Imagine three arrow vectors sitting at the origin, they point X,Y,Z,
this represents mass, electical, and magnetic.
The arrows must maintain the same overall vector length
X+Y+Z = k. However, they can fluctuate.

If a photon collides with something it regains its mass, so the
electrical and magnetic portions are gone, if the photon then
reflects it again has no mass, but electical and magnetic.

In a solar panel the photon collides, gains mass, but then at
lower frequencies it's conduductive, so only a portion is
reflected as radiation, an electron sized chunk of the energy
goes off down the wires.

As an electron is excited to high frequencies by equipment,
many of the components (like wires) have high resistance to
high frequencies.  That is why lasers use rubies, or gas tubes,
they are controlable high frequency oscilators that are still
conductive at optical frequencies.

That is also why you can fit more information down a fiber-
optic line than a copper line, fiber can operate at higher frequencies.

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