The Extraordinary Properties of Water

Water threeA water molecule (H 2 O), is made up of three atoms --- one oxygen and two hydrogen. H H O

Water is Polar oxygen atom attracts more electronsIn each water molecule, the oxygen atom attracts more than its "fair share" of electrons oxygennegativeThe oxygen end “acts” negative hydrogenpositiveThe hydrogen end “acts” positive POLARThe positive and negative ends causes the water to be POLAR

Interaction Between Water Molecules Negative Oxygen end of one water molecule is attracted to the Positive Hydrogen end of another water molecule to form a HYDROGEN BOND

What are the Properties of Water?

Cohesion Attraction between particles of the same substance (why water is attracted to itself)Attraction between particles of the same substance ( why water is attracted to itself) Results in Surface tension (a measure of the strength of water’s surface) Results in Surface tension (a measure of the strength of water’s surface) Produces a surface film on water-allows insects to “walk on water”Produces a surface film on water-allows insects to “walk on water”

Surface Tension Helps insects walk across water

Adhesion Attraction between two different substances. Attraction between two different substances. Water will make hydrogen bonds with other surfaces such as glass, soil, and plant tissues. Water will make hydrogen bonds with other surfaces such as glass, soil, and plant tissues.

Adhesion Also Causes Water to … Form spheres & hold onto plant leaves Attach to a silken spider web

Adhesion Causes Capillary Action Cohesion and adhesion together allow capillary action which gives water the ability to “climb” structures

Water is Less Dense as a Solid Ice is less dense Ice is less dense as a solid than as a liquid (ice floats) due to hydrogen bonding. No other substance is less dense as a solid. Prevents water from freezing from the bottom up.

Homeostasis Ability to maintain a steady state despite changing conditions.Ability to maintain a steady state despite changing conditions. Water is important to this process because:Water is important to this process because: a. Resists temperature change b. Ice protects against temperature extremes (insulates frozen lakes)

Solutions Water is usually part of a solution.Water is usually part of a solution. There are two parts to a solution:There are two parts to a solution: SOLUTESOLUTE –Substance that is being dissolved SOLVENTSOLVENT –Substance into which the solute dissolves –Ex. Salt water

Solution