Here's a breakdown:

* Electronegativity: Oxygen is more electronegative than hydrogen. This means oxygen has a stronger pull on the shared electrons in the O-H bonds. This creates a partial negative charge (δ-) on the oxygen atom and partial positive charges (δ+) on the hydrogen atoms.

* Molecular Geometry: Water has a bent molecular geometry due to the two lone pairs of electrons on the oxygen atom. This bent shape means the partial positive charges on the hydrogen atoms are on one side of the molecule, and the partial negative charge on the oxygen is on the opposite side. This separation of charge creates a dipole moment, making water a polar molecule.

In summary: The combination of electronegativity difference and molecular geometry leads to a significant charge separation in the water molecule, making it polar.