Question is what exactly title says that have we ever seen an atom through any means (microscopes/equipments.etc)? If not, how do we know they exists?

  • $\begingroup$ Did you try Google? Imaging of atoms has been accomplished recently, and it's big news. There are really two questions here: 1) What do atoms look like? and 2) How did we know atoms existed before they could be imaged? $\endgroup$ – Blackbody Blacklight Apr 27 '14 at 8:05
  • $\begingroup$ possible duplicate of Can we make images of single atoms? $\endgroup$ – John Rennie Apr 27 '14 at 8:08
  • $\begingroup$ Google STM (scanning tunneling microscope) or AFM (atomic force microscopy). And how do we know they exist... well the answer is physics... $\endgroup$ – dingo_d Apr 27 '14 at 8:09
  • $\begingroup$ Historically the combination of stoichiometry, the behavior of gasses as compared with the thermodynamics of the "ideal gas" and Einstein's explanation of Brownian motion taken together were considered sufficient proof. $\endgroup$ – dmckee --- ex-moderator kitten Apr 27 '14 at 14:28

Scanning tunneling microscopes can "see" atoms. Here is a 2008 issue of Nature magazine:

enter image description here

What you're really seeing here is an electrical equipotential surface, which is close enough to being a solid surface for most purposes. A scanning tunneling microscope (or the similar atomic force microscope) is like a very precise phonograph; it traces over a surface and senses the atomic-scale bumps in a surface. It's not too much inference to assume that the atomic-scale bumps are really atoms. The colors are added though; any atom is smaller than a wavelength of visible light.

How did we know atoms existed before that? Well, that's quite a story, and Wikipedia probably tells it better than I can.


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