Water Properties SC.912.L.18.12 Water has unique properties that make it an important substance for life.

Cohesion and Adhesion Hkhkhjhkjhkh Cohesion is an attraction between substances of the same kind. Example: Hydrogen bonds between water molecules cause the cohesion of liquid water. Because of cohesion, water and other liquids form thin films and drops.

Adhesion Adhesion is an attraction between different substances. Water molecules are attracted to many other similarly polarized substances Example: Adhesion powers capillary action, where H20 molecules move upward thru a narrow tube, such as the stem of a plant.

Stores Heat Energy Water absorbs heat more slowly and retains this energy longer than many other substances do. Many organisms release excess heat through water evaporation. Example: Humans cool themselves by sweating. The water vapor lost through the evaporation of sweat carries heat away from the body.

Universal Solvent Water has the ability to dissolve many substances. The polarity of water enables many substances to dissolve in water. Example: Ionic compounds and polar molecules dissolve best in water

Surface Tension Water molecules like to cling to one another. At the surface, there are fewer water molecules to cling since there is air above (no water molecules). This results in a stronger bond between those molecules that actually do come in contact with one another and a layer of strongly bonded water. Example: Small insects such as the water strider can walk on water because their weight is not enough to penetrate the surface.

Why is water a good solvent for many ionic compounds? Review Questions: Why is water a good solvent for many ionic compounds? Water has the ability to store heat longer than other substances. What benefit does this property of water provide to organisms?