That right there is a screenshot from AtomAnimation, a website that seems to do nothing more than provide animations of Bohr models for any element with any combination of protons, neutrons, and electrons.
It's kind of fun to play around with, though I warn you that the larger atoms take a decent amount of time to render and seemed to slow my browser down a bit while they were running.
Around 0:50 into the video, our meandering narrator mentions that he wasn't able to find a single source with correct, complete information on the history of the Avogadro Number...which makes me wish he'd provided sources for his information. Otherwise, how do we know that what he's telling us is correct?
(As an aside, I've always called it Avogadro's Number. Maybe the the and lack of possessive is a British thing. I'll admit that I don't remember how my professors at the University of Aberdeen referred to it.)
I will say that this is an amazingly thorough and likely correct history of the development of the concept and number of the moles. It goes through from Democritus through the Karlsruhe Congress and all the way to the modern measurement of Avogadro's number via a nearly perfect sphere of silicon.
I need to watch this video a few more times until I'm more familiar with all the steps in this development so I can tell the story to my students.
Just let the comedy wash over you.
They're all funny, but I really enjoy the third joke. I'm in the really small overlap area, apparently.
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| Rollover joke - The Earth is, on average, located in the habitable zone, but at any given time it has a certain probability of being outside it, which is why life exists on Earth but is mortal. (Source - XKCD) |
See, it's funny because most of the time, the atom - particularly the Bohr model of the atom - is likened to the solar system with electrons following 'orbital' paths around the nucleus the way that planets follow similar paths around the sun.
As a chemistry teacher, I can say that it's much, much harder to come up with a similarly easily understood analogy for how electrons exist in the quantum mechanical model of the atom. There just isn't any sort of macroscopic thing that is anything like the quantum mechanical model of the atom.
And if the planets did move like electrons, that would be somewhat terrifying - especially as electrons can teleport from region to region a la an electron in a box.
Though I do have some evidence that the planets have a measurable spin, so there is that, at least.
Any visible lump of matter - even the merest speck - contains more atoms than there are stars in our galaxy. When we lift an apple we feel the total weight of a colossal number of almost weightless atoms. When we hear the ripple of water we are hearing shockwaves as a myriad of almost imperceptible molecules crash down and collide with other molecules. When we dress we pull across our bodies a great web spun from the infinitesimal dots and held together by the forces acting between them. When we see a flame we are seeing the release of an almost negligible droplet of energy, but in such a Niagara that the heat sears and consumes. - PW Atkins, Molecules (page link)
The simple notion that everything we are...everything we see...everything we can ever touch, see, hear, taste, or feel is made up of dots of nothing so miniscule as to almost not exist singly...that the combined might of these imperceptible bits of nothingness can crush, deafen, poison, blind, or stun you with their beauty and grandeur...is amazing to me.