Properties of Water

Capillary Action

Water climbing from the roots to the top of a plant through small tubes. The water sticks to itself (cohesion) and to the side of the tube (adhesion).

Polarity

Water is a polar molecule. The oxygen holds the electrons more tightly than the hydrogen. The oxygen end of the molecule has a slight negative charge. The hydrogen end of the molecule has a slight positive charge.

Adhesion

Water molecules stick to other molecules that have a positive or negative charge.

Cohesion

Water molecules stick to other water molecules because of the weak hydrogen bonds. This causes surface tension and allows some organisms to walk on the surface of the water.

High Specific Heat

When molecules go from a liquid to a gas (evaporate) the attractions between the different molecules is broken. Because water forms hydrogen bonds between the molecules it takes a lot more energy to increase the temperature of water. This means that water does not change temperature easily. This is important because cells are mainly made of water. This allows organisms to maintain homeostasis and not change temperature quickly.

Surface Tension

the tension of the surface film of a liquid caused by the attraction of the particles in the surface layer by the bulk of the liquid, which tends to minimize surface area.

Low Density of Solid water

Water expands as it freezes. This causes ice to float on the surface of the water. This is important because the ice provides a barrier in frozen lakes between the water at the bottom of the lake and the air. It allows for living organisms to survive the winter and keeps the lake from freezing solid. (This is also why cells burst when they freeze)

Neutral PH

Water has a pH of 7. This is important because water makes up most of our cells. If water was acidic or basic it would destroy many of the organelles in the cell.

Universal Solvent

Water has the ability to dissolve many compounds and molecules that have a charge. Ex: Water dissolving salt or sugar This is important because cells and blood are mainly water. This allows them to contain dissolved salts and gases.

Hydrogen Bond

Water molecules will form weak bonds between the positively charged hydrogen from one molecule and the negatively charged oxygen from another water molecule. The bonds formed between the water molecules is the reason for most of the properties of water!