I came across a copy of Poul Anderson's essay Uncleftish Beholding ("Atomic Theory") again today (through dotaturls) and read through it. Fun stuff.
It also made me think about how "childish" some of the words sound... yet there's nothing particularly "grand" or "learnèd" about Greek or Latin words to Greek or Latin speakers, and I suppose something like "velocity" (well, "velocitas") is just as common to a Roman as "haste" is in English. (Related: my amusement at Swedish "hastighet" for "speed" and Dutch "hoeveelheid" for "quantity"; they sound a bit silly to my German ear when I imagine their cognates, "Hastigkeit" and "Wievielheit", but again, it depends on what you're used to—"Geschwindigkeit" also starts to sound funny if I think about it too much, after all, perhaps since "geschwind" is not in use much these days.)
So it all depends on what you're used to, and what specific scientific jargon meanings you attach to native words. There's no law saying that to discuss science, you have to use Greek- and/or Latin-derived forms, otherwise communication or precision is impossible.
It's also interesting to see where German uses less Romance than English; indeed, translating some of the unfamiliar English words morpheme-by-morpheme into German makes it a lot easier to understand the text. (For example, "bestands of" for "consists of"; cf. "besteht aus".) Though for some, particularly more technical ones, you do have to have recourse to Greek or Latin (e.g. "samestead" < "isotope").