Here's why:

* Shape: Water molecules have a bent shape due to the two lone pairs of electrons on the oxygen atom.

* Electronegativity: Oxygen is more electronegative than hydrogen, meaning it attracts electrons more strongly.

* Charge Distribution: The oxygen atom in water has a partial negative charge (δ-), while the hydrogen atoms have partial positive charges (δ+). This uneven distribution of charge creates a dipole moment, making the molecule polar.

Think of it like this: The water molecule is like a tiny magnet with a positive and negative end. This polarity is crucial for many of water's unique properties, such as:

* Strong hydrogen bonding: Polar water molecules form strong hydrogen bonds with each other, leading to high surface tension, high boiling point, and the ability to dissolve many polar substances.

* Excellent solvent: Water's polarity allows it to dissolve many ionic compounds and polar molecules, making it an excellent solvent for life processes.