From what I know, the cooling of He-4 atoms causes them to fall into the ground state, making them Bosons. But there's something which confuses me, from what I read, these atoms actually coalesce into one "super-atom". And in quantum theory, it is entirely possible for many atoms to be in one spot at the same time (right?). But why is it that BECs are not the size of atoms? Or is my understanding of BECs flawed around here?