

Hydrogen Atom - Scale Model - kingkawn
http://www.phrenopolis.com/perspective/atom/

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gort
Is this actually physically correct? I was under the impression that "width of
an electron" isn't something we have a good value for, if it's a meaningful
quantity at all...

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swombat
You're right. The electron is a point particle. It has no size (though,
interestingly, it has angular momentum - i.e. it spins on itself. Go figure).

I guess the page is intended to render the distance between the proton and the
electron rather than the size relationship between the two.

On the other hand, even that is somewhat dubious. Electrons aren't located in
a single place, they can be anywhere within a certain area, according to their
probability density function - including right in the middle of the proton,
though the probability of that is low.

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teeja
I saw that page and went 'really'??

[http://www.scribd.com/doc/15911579/Derivation-of-
Fundamental...](http://www.scribd.com/doc/15911579/Derivation-of-Fundamental-
Particle-Radii-Electron-Proton-Neutron)

From that article, the ratio Rp to Re is about 83. But the more I look, the
more answers I find. Scienceworld has 0.80+ fm for the proton, is silent on
the electron. Comparing the following two (Physics Factbook), they could be
about equal. "The electron is a point-like particle-that is, a particle with
no measurable dimensions, at least within the limitations of present-day
instrumentation. "

<http://hypertextbook.com/facts/2000/DannyDonohue.shtml>

<http://hypertextbook.com/facts/1999/YelenaMeskina.shtml>

Doesn't nullify the point that atoms are empty space - but comparing radii is
risky business.

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sp332
It's actually a limit of the model, not of the measuring device. The electron
has angular momentum, but even if it were only as big as the smallest allowed
size in quantum mechanics (Plank's constant), the speed of rotation would be
faster than the speed of light. Since this is impossible, the model just
defines the size of the electron as 0.

<http://en.wikipedia.org/wiki/Plank%27s_constant>

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jrockway
This does not work in Firefox.

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wgj
It works in Chrome. And you can drag the scroll bar to get there much quicker,
rather than clicking.

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snarkyturtle
This coupled with the size of the largest stars is truly mind-boggling (much
less the size of the universe or the size of a quark). It's amazing how we
humans, as primitive as we are, can at least have an idea of the scale of the
universe. All through pictures and ideas.

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algorias
But there's a difference between being able to reason about the magnitude of a
number theoretically, and actually visualizing such a distance in your mind,
which I find incredibly hard to do.

11 miles radius at a resolution of one pixel's width. That's like visualizing
an entire city, from close enough to distinguish cracks in the sidewalks.

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seldo
The horizontal scroll doesn't work in Firefox 3/win :-(

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eam
Did anyone actually scroll all the way?

