[voice | private]
Well, yeah. You know how molecules bump up against each other at certain speeds, right? Solid molecules are faster than liquid, which's faster than gas...
If I move quick enough, I can get myself so that I'm moving faster than each individual molecule. Can't damage something I can't even touch, right? It's that kind of idea. [Pseudo-science! Bart's no chemistry expert, but he's got the basics down pat.]