Atomic Evidence

I asked another question about pictures of atoms and you said there is no actual picture... So how do we know that there is all that stuff in an atom? How do we know there are electrons, neutrons and protons and that they are all in the order we say they are. Is all this just a guess or is there and actual proof? thanks
- James

There’s an enormous amount of evidence that our description of atoms is correct. That includes very accurate predictions of the absorption/emission spectra of light, detailed predictions of all the magnetic properties of the nuclei and electrons, predictions of what sorts of particles come out when atoms collide, predictions of what happens to atoms when they’re crowded together or heated up or cooled down, and on and on. A ’picture’ wouldn’t amount to much in comparison with the detail, precision, and variety of the confirmations of our current description of atoms.

As for electrons, neutrons and protons, they are observable separately from atoms. For example, ordinary CRT screens use beams of electrons to excite the phosphors.

One thing that ordinary science classes obviously don’t teach is the unity of science. We don’t just have a bunch of little pictures on pages but rather a deeply interconnected net of theory and experiment. And theory is not the sort of verbiage that you read in other areas but real mathematical structure with precise predictions.

Mike W.

(published on 10/22/2007)