Video narration
Why do separate water molecules cling together, making droplets hold their shape? When you see water sticking to itself, the answer starts inside each molecule. Oxygen pulls shared electrons more strongly than hydrogen. So oxygen becomes slightly negative, while hydrogen becomes slightly positive. These are partial charges-not full charges, but enough to matter. Here's the turn: a hydrogen bond is not the bond holding hydrogen and oxygen together inside one molecule. It is the attraction between a partly positive hydrogen on one water molecule and a partly negative oxygen on a neighboring one. One attraction is weak compared with the bonds inside a molecule. But across a droplet, many molecules tug on nearby molecules. That shared pull helps water stay together and gives it distinctive behaviors. So what makes separate water molecules cling together? Their partial charges make neighboring molecules attract. That attraction is a hydrogen bond.