 Water has many properties that make it important for supporting life. One of these properties is that solid water, or ice, is less dense than liquid water and therefore floats. Have you ever thought about why ice keeps float in your drink? The hydrogen bonding between water molecules is responsible. In liquid water, these molecules are constantly moving and the hydrogen bonds break and reform. In ice, since the temperature is lower, the molecules are moving less and the bonds are stabilized, forming a lattice. The lattice traps air, making ice less dense than water and making it float. What would happen if ice sank? In winter, as the cold air hit the liquid water, it would freeze and sink to the bottom of the lakes or ponds. The liquid water would continue to be exposed to cold air and layers of ice would continue to sink until all the water in the bodies of water were frozen. There wouldn't continue to be life in bodies of water during the winter and even during the summer. The warm air wouldn't be able to thaw more than just the top layer of the frozen bodies of water, making it so there isn't enough liquid water on the earth to support life. Therefore, the hydrogen bonding in water that causes ice to be less dense than water is critical in supporting life.