Polarization and Why Neutral Things Get Attracted

Every atom has a positively charged nucleus surrounded by a cloud of negative electrons. Bring a charged rod near a neutral object and its field reaches into every atom. If the rod is negative, it pushes each electron cloud slightly away and leaves the nucleus side slightly exposed; if the rod is positive, it pulls the electron cloud slightly closer. Either way the atom's charge is no longer perfectly centered. It becomes a tiny dipole: a little negative on one side, a little positive on the other, with the same total charge it always had.

Now add up the whole object. One side ends up with a thin skin of charge opposite the rod's sign, the other side a thin skin of the same sign. Both feel a force from the rod, one attractive and one repulsive, and the two forces would cancel if the distances were equal. They are not. The opposite-charge skin sits closer to the rod, and electric force weakens with distance, so the attraction is stronger than the repulsion. The near side wins, and the whole object gets tugged toward the rod even though it never gained or lost a single electron.

This is why a charged balloon can bend a thin stream of water or lift bits of paper: no charge has to transfer at all, only shift internally. It sets up the next idea in the unit, induced charge separation on conductors, where free electrons move much more easily than in insulators and the same near-side-wins logic explains stronger induced effects.