What Does An Atom Look Like?

If you remember, I had mentioned in an earlier article:

"Atoms don't actually look like this. They look like this. But that's a story for another time".

I think that it's about time that I finally expanded on this - in a semi-scientific, semi-historic sort of way.

The atom was, and is, a pretty revolutionary concept, but what exactly it looked like had been somewhat of a mystery.

When the greeks first proposed the idea of the atom, they believed that the atom that made up the substance must look like the substance itself. So cheese atoms were really small bits of cheese, and pizza atoms were really small bits of pizza.

We moved past that idea once the electron was discovered, and instead we had the plum pudding model. This model was proposed by J J Thompson in 1897, and it consisted of a sea of electrons surrounded by a pervading positive charge. There was no nucleus in sight for this model, as neither the proton or the neutron had been discovered.

You can have a look at this model here.

This model was the most prominent one, till Rutherford came along with his Gold foil experiment.

The proton had already been postulated at this point - but the general consensus was that the atom was really just a jumbled sphere of charge. In Rutherford's experiment, he shot laser beams at a piece of gold foil in order to see where it would land up.

What he found was that the vast majority of laser beams would simply go straight through the foil, and only a very small minority would bounce off in some other direction.

This lead Rutherford to believe that the majority of the atom must then be empty space, with the majority of the mass in the centre and electrons orbiting around this mass.

After the neutron was discovered, we then had the atomic model that we all seem to know and love, the orbital model.

You may have imagined that the article would end here. But it doesn't - because that model is in fact, wrong.

Now, it isn't entirely wrong, but it just doesn't tell the whole truth. Electrons don't have one constant, set position, and instead behave as a wave. To draw the electron as some single point is a lie, because that's not really its behaviour.

An electron within an atom has numerous possible locations it may be at within any given time, with some areas of a higher probability than others (if you're not following, check out this article about Heisenberg's Uncertainty Principle).

The most up to date model we have so far is this one, not the one you were perhaps more familiar with.

So that is what an atom looks like! A nucleus with electrons behaving as waves surrounding it.

the picture above also depicts a fake electron.

http://www.physlink.com/education/askexperts/ae46.cfm

https://www.youtube.com/watch?v=5pZj0u_XMbc

http://education.jlab.org/qa/history_04.html

https://www.youtube.com/watch?v=thnDxFdkzZs