What does an atom look like?

Factual Questions
1

We all know how small it is. I’m sure many have seen that supposed “IBM” written in atoms. But since it is a physical “thing,” it must have a “shape” that is visible to the human eye.

I mean, I am composed of atoms. Therefore, I am visible. But does an atom look like that old stereotype of five hoops around a central orb? (Even supposing one could visibly perceive the orbiting particles.)

So is it perfectly round? Like so perfectly round it’s 100% perfect? Or does it have a bulge or two? Does it float in some invisible “gel” that comprises the rest of matter?

I hate waking up at 4 a.m. trying to figure this stuff out.

2

It would be round, fuzzy, and light pink.

3

It isn’t possible for us to directly ‘see’ atoms because seeing normally involves bouncing photons off things and atmos are (individually) too small for that.

Also, atoms aren’t (as far as I understand it) ‘physical’ things in the classical sense of being composed of some kind of solid spheres.

And unless you count electromagnetic forces or spacetime, there is no ‘gel’ that composes the rest of the matter - matter is atoms.

4

The problem is that you can’t see atoms. So an atom doesn’t look like anything. The best way to visualize it would be a fuzzy spherical cloud, but that’s just a way of making our (limited) human brains deal with something beyond its ability to concptualize.

5

One of the problems with understanding atoms, is you say it “must” have a shape. Someone will come along later to explain.

6

Right, what John said…

Still looks pink to me though…

7

Well, that depends what you mean by “see”.

As tonbo0422 alluded to, researchers at IBM’s Almaden research center wrote “IBM” using xenon atoms on a nickel surface. You can see an image here: http://www.almaden.ibm.com/vis/stm/images/stm10.jpg

As you might guess, it’s not like that image is a photograph. That image was constructed by gathering data from a STM (scanning tunneling microscope). The atoms were also moved into that shape using the STM, and into many other shapes, as shown in the gallery: http://www.almaden.ibm.com/vis/stm/gallery.html

What we’re seeing in these images are the electromagnetic interactions between the STM “tip” and the atoms, which might seem like a cheat (we’re not really seeing the atoms themselves)… but your eye just uses a different type of electromagnetic interaction with reflected photons to see anything, so it’s close enough.

No, you can’t really see an atom. But there are certain properties about it that are more than a model.

First, forget everything you’ve ever seen about electrons orbiting in rings around the middle (nucleus) of the atom. That model was proven wrong within a few years of its introduction, yet it somehow persists.

An atom is actually composed of a nucleus surrounded by a cloud of electrons. The nucleus is made of protons and neutrons, but it’s probable that they aren’t really divided into individual particles when they’re in the nucleus, so it’s safe to just think of the nucleus as roughly a sphere. The electrons have a wavelength roughly equal to the diameter of the atom–meaning they aren’t really in any particular place (thus the cloud surrounding the nucleus, even if there’s only a single electron, such as in a hydrogen atom).

BTW, the reason you’re visible is that electrons are able to absorb certain photons, while other photons are reflected (either by “bouncing off” of the nucleus, or by being absorbed and re-emitted by the electrons). Different atoms (and arrangements thereof) have electrons that absorb different wavelengths (colors) of photon, resulting in different colors of photons being reflected to be picked up by your eye.

8

The difficulty in moving towards 20th century physics was losing the assumption that the way things are on the human scale is somehow special, and that things should be like that on the very large and very small scales. They aren’t. Atoms do not have a shape, a color, or any property that you would use to understand the objects you encounter.

9

That bugs the hell out of me. The answer is almost more annoying than the question.

10

You think that’s bad? You should see what the modern theories say.

11

If you get the video by National Geographic called The Invisible World, it shows what atoms look like through an election microscope (i think that’s what it is) in real time. They basically look like fuzzy circles that dance around.

12

Here is an excellent description:

http://boards.straightdope.com/sdmb/showthread.php?postid=3278352#post3278352

13

This question is like asking, “What does truth look like?” It is an unanwerable question because an atom’s structure can’t be seen by photons. We can use various techniques to understand what the structure of an atom is like, but it doesn’t “look” like anything.