Both of those beliefs are false, of course:
The Earth orbits the centre of mass of the solar system (as does the Sun).
Even a small drop of water has vastly more than two hydrogen atoms and one oxygen atom in it.
Agreed.
But telling people that the Earth and Sun are both in orbit of the mass of the solar system just confuses most people.
Indeed this is how we detect stars with planets by detecting the 'wobble'.
But the fact remains that belief in orbits is not strange, even if what is being believed seems strange. The reason is that the beliefs are supported by evidence.
Contrast this with a belief in say aliens abduction. We know abduction happens, we understand that life could exist elsewhere, but belief that they are coming here to abduct people is still strange as the evidence to support it, is just anecdotal.