Democritus is only the go to name because he’s in the scientific mythology as one of the brief “ancient names” mentioned to add important Classical References to the heroes and acts of the early modern project of “Science”
the way that science ended up developing (i.e. away from Christ to an extent that would alarm most of the saints in the early modern part of the scientific mythology), it would seem that the number one Classical Ornament to scientific atomism, to be included in the schoolboy hagiographies, should be Lucretius, whose On the Nature of Things anticipated a lot more of scientific atomism and its consequences than Democritus.
This is to be expected from a brief comparison of the two philosophers: Democritus was a filthy pre-Socratic who has the usual symptoms of a) having only a few surviving fragments, b) being viewed through his Academic enemies and c) living at the beginning of the rationalist end of Antiquity. On The Nature of Things is the product of 500 further years of rationalists thinking hard about the consequences of classical atomism whilst living in rationalist ideoreligions such as Epicureanism
But he isn’t. I think this is for several reasons.
I think firstly because the purpose of the “ancient names” is just to add colour to teaching physics, like dropping Phoebus or Jupiter in an early modern occasional poem, and Democritus is as good a name as Lucretius.
Secondly, because until the 20th century it was indecent to be an Epicurean (and almost mandatory now in official Science), but pre-Socratics are mysterious enough to be vague Pagan worthies.
Thirdly, although Lucretius was known in the Renaissance, the love of him doesn’t get into the right circles – the Royal Society has someone who translates him into English, but the people who Fucking Love him are all Italian politicians or, later, weird Germans like Goethe who also don’t fit into the standard hagiography.
Fourthly, I think the development of scientific atomism happened late enough (i.e. the late 19th and early 20th centuries) that the people involved had moved beyond any emotional need to find Ancients to attach to their ideas, so they retained the figure of Democritus out of inertia.
Around the same time they quickly worked out atoms weren’t atomic and somehow this surprise got attached to the commonplace you see above, and that I heard several times as a schoolchild that Democritus (here acting as a metonym for classical atomism) was a silly because you can split atoms after all!
This is unsound thinking because it is the application of Particle Physics Brain to science (see also the strange charisma, big swinging dicks and loud voices to dictate the 20th century chapter of the scientific hagiography that particle physicists had until quite recently when it became apparent the bottom had fallen out of the field some time ago without anyone noticing). Scientific atomism was a productive theory before particle physicists attempted to split atoms apart, because it put all chemistry on a rational footing which is not nothing – because if you put chemistry on a rational footing (Dalton working out accounting tricks in the early 19th century), you also put biochemistry on a rational footing (our hero Wöhler synthesises urea blah blah), and when you do that you put biology on a rational footing (this part is washed over because there doesn’t seem to be any clear point between Wöhler and the molecular biologists where Scientists stopped being vitalists) and when you do that you put Epicureanism on a rational footing. All of this without caring very much about how strong the binding of the internal structure of atoms is. And it is this sort of atomism that is developed by the classical atomists, albeit poorly.