Properties of Water

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Produces a surface film on water that allows insects to walk on the surface of water

Slide 14

Cohesion …

Helps insects walk across water

Slide 15

Adhesion

Attraction between two different substances.

Water will make hydrogen bonds with other surfaces such as glass, soil, plant tissues, and cotton.

Capillary action-water molecules will “tow” each other along when in a thin glass tube.

Example: transpiration process which plants and trees remove water from the soil, and paper towels soak up water.

Slide 16

Adhesion Causes Capillary Action

Which gives water the ability to “climb” structures

Slide 17

Adhesion Also Causes Water to …

Form spheres & hold onto plant leaves

Attach to a silken spider web

Slide 18

High Specific Heat

Amount of heat needed to raise or lower 1g of a substance 1° C.

Water resists temperature change, both for heating and cooling.

Water can absorb or release large amounts of heat energy with little change in actual temperature.

Slide 19

High Heat of Vaporization

Amount of energy to convert 1g or a substance from a liquid to a gas

In order for water to evaporate, hydrogen bonds must be broken.

As water evaporates, it removes a lot of heat with it.

Slide 20

High Heat of Vaporization

Water's heat of vaporization is 540 cal/g.

In order for water to evaporate, each gram must GAIN 540 calories (temperature doesn’t change --- 100oC).

As water evaporates, it removes a lot of heat with it (cooling effect).

Slide 21

Water vapor forms a kind of global ‘‘blanket” which helps to keep the Earth warm.

Heat radiated from the sun warmed surface of the earth is

absorbed and held

by the vapor.

Slide 22

Water is Less Dense as a Solid

Ice is less dense as a solid than as a liquid (ice floats)

Liquid water has hydrogen bonds that are constantly being broken and reformed.

Frozen water forms a crystal-like lattice whereby molecules are set at fixed distances.

Slide 23

Water is Less Dense as a Solid