NN writes:
You imagine a teaspoon full of atoms moving around to occupy your volume? But somehow, the composition of your hair, for example does not change?
Giving Vanessa the benefit of the doubt, I imagine she means on an atom-by-atom basis.
Not in a "My body is a bag of electrons and neutrons which whirl around like bees in a sack" way.
Instead, what I think she has done is got completely confused about what an atom is.
Perhaps she meant electrons and neutrons? Who knows.
Either way, any sentence that starts with "I once heard..." is going to be lacking any real knowledge of the subject.
CRYSTALS!!