Here's why:

* Oxygen is more electronegative: Oxygen has a stronger pull on electrons than hydrogen. This means the shared electrons in the O-H bonds spend more time closer to the oxygen atom.

* Uneven charge distribution: This unequal sharing of electrons creates a partial negative charge (δ-) on the oxygen atom and a partial positive charge (δ+) on the hydrogen atoms.

* Polar molecule: The uneven charge distribution makes water a polar molecule, with a negative end (oxygen) and a positive end (hydrogen).

This polarity is crucial for many of water's important properties, including its ability to dissolve many substances and act as a solvent.