Now, the small size of the positively charged hydrogen atom of one molecule, for example, let's say this molecule allows it to get very close to the negatively charged oxygen of another molecule. For example, this molecule right here, the small size of this allows it to get very close to this oxygen. And this small distance basically means we have a very strong interaction. And this type of strong intermolecular interaction, or intermolecular bond, is known as a hydrogen bond. So we see the fact that water is a polar molecule. And because it consists of these very tiny H atoms, we form these very strong intermolecular bonds, known as hydrogen bonds, when many of these water molecules actually are found in close proximity.