Here's why:

* Hydrogen bonds are a type of weak intermolecular force that occurs between a hydrogen atom covalently linked to a highly electronegative atom (like oxygen in water) and an electron pair in the adjacent molecule.

* Water molecules have a bent shape due to the two lone pairs of electrons on the oxygen atom. This shape creates a partial negative charge on the oxygen atom and partial positive charges on the hydrogen atoms.

* The dotted line symbolizes the electrostatic attraction between the partially positive hydrogen atom of one water molecule and the partially negative oxygen atom of another water molecule.

These hydrogen bonds are responsible for many of water's unique properties, including its high boiling point, high surface tension, and its ability to act as a solvent for many substances.