1. State of Matter: Water exists in all three states of matter: solid (ice), liquid (water), and gas (water vapor). This is due to the strong hydrogen bonds between water molecules.

2. Density: Liquid water is denser than ice, which is why ice floats. This is an unusual property for substances, and it's essential for life in aquatic environments.

3. Boiling Point: Water has a relatively high boiling point (100°C or 212°F) compared to other similar molecules. This is again due to the strong hydrogen bonding.

4. Surface Tension: Water has a high surface tension, meaning it can resist being broken. This is why water droplets form and why some insects can walk on water.