How did we get from the atom to the string?
Well, before string theory, there were elementary particles- lots of them. Electrons, muons, and quarks. And to just try and convey the idea, I'll just draw a little dot- which is meant to symbolize a point particle. And as I said, there are lots of them. Electrons, muons... some of them better known to the public, some less. Like maybe you haven't heard of taus, but in my line of work they're important "beasts."