Look at the solid clump of concrete. What if I told you it was mostly empty space? That it was not solid matter clumped together, but rather held mostly by a force field? Science fiction?

If nucleus of an atom were the size of a marble, then the electron would be size of the thickness of a human hair. That's not the cool part. The cool part is that the electron would be 4 kms away from the nucleus at that scale. You heard it, 4 kms, about 2 miles! So an atom is mostly empty space. That solid clump of metal aint that solid afterall!