the extraordinary properties of water courtesy of kate morkeski

The Extraordinary Properties The Extraordinary Properties of Waterof Water

Courtesy of Kate Morkeski http://genbio.biol.vt.edu/tapages/morkeski

http://madsci.wustl.edu/posts/archives/aug98/900528149.Bc.r.html

The extraordinary properties of The extraordinary properties of WaterWater

A water molecule (HA water molecule (H22O), is made O), is made

up of three atoms: one oxygen up of three atoms: one oxygen and two hydrogen.and two hydrogen.

http://www.e-spaces.com/broadcast/Water/scr2.html

H

HO


•At sea level, pure water boils at 100 °C and freezes at 0 °C.

•The boiling temperature of water decreases at higher elevations (lower atmospheric pressure). PV=nRT

•For this reason, an egg will take longer to boil at higher altitudes.


CohesionCohesion AdhesionAdhesion High Specific HeatHigh Specific Heat High Heat of VaporizationHigh Heat of Vaporization Less Dense as a SolidLess Dense as a Solid

CohesionCohesion is the property of water that causes it to be attracted to itself.

•Surface tension, a measure of the strength of water’s surface, is the direct result of cohesion.

•The strong film on the surface of water is a result of the attraction between water molecules. This property allows insects to walk on the surface of water and the creation of waves.

Water strider

Cohesion

Adhesion

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

•Water molecules will “tow” each other along when in a thin glass tube. This is called capillary action. This is the same process by which plants and trees remove nutrients from the soil, and paper towels soak up water.

.

Adhesion

High Specific Heat

•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.

http://www.ec.gc.ca/water/index.htm

““Water vapor forms a kind of Water vapor forms a kind of global ‘blanket’ which helps to global ‘blanket’ which helps to keep the earth warm. Heat keep the earth warm. Heat radiated from the sun-warmed radiated from the sun-warmed surface of the earth is surface of the earth is

absorbed and held absorbed and held

by the vapor.”by the vapor.”

High Heat of Vaporization

• In order for water to evaporate, hydrogen bonds must be broken. As water evaporates, it removes a lot of heat with it.

•Thus, the heat of vaporization refers to the amount of energy required to convert water from a liquid to a gas.

High Heat of Vaporization

• Meteostat 5 water Vapor Imagery morning of 9/5/2004

Courtesty of http://www.goes.noaa.gov/

Water is Less Dense as a Solid

•Ice is less dense as a solid than as a liquid.

•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.


•Which is ice and which is water?

http://www.nyu.edu/pages/mathmol/modules/water/info_water.html


Water Ice

Density of waterDensity of water

If density of object is = to or < than water it will float. If density of object is = to or < than water it will float. If the object’s volume displaces an amount of water If the object’s volume displaces an amount of water

equal to the weight of the object it will float.equal to the weight of the object it will float. Displacement is how steel ships can float even Displacement is how steel ships can float even

though the density is greater.though the density is greater. Density of pure water is 1.0Density of pure water is 1.0 Density of pure ice is 0.92. Density of pure ice is 0.92. Density of sea water is 1.03.Density of sea water is 1.03. Icebergs are made of pure water will float with a ratio Icebergs are made of pure water will float with a ratio

of more ice above the surface than that of an ice of more ice above the surface than that of an ice cube.cube.


Why talk about water?Why talk about water? In the fossil record, in what habitat do we In the fossil record, in what habitat do we

first observe life?first observe life?

HomeostasisHomeostasis

Steady stateSteady state Constant physiological condition of cells, Constant physiological condition of cells,

organisms global ecosystemsorganisms global ecosystems a. Makes a good insulatora. Makes a good insulator b. Resists temperature changeb. Resists temperature change c. Universal solventc. Universal solvent d. Coolantd. Coolant e. Ice protects against temperature extremese. Ice protects against temperature extremes

Bond TypesBond Types

CovalentCovalent HydrogenHydrogen ElectrostaticElectrostatic Van der WaalsVan der Waals

Implication of Hydrogen BondingImplication of Hydrogen Bonding

Ice floatsIce floats: density of solid water is less : density of solid water is less than liquidthan liquid

CohesionCohesion:: the the intermolecular intermolecular forces forces between particles of a substance, in this between particles of a substance, in this case, watercase, water

AdhesionAdhesion: the : the intermolecularintermolecular forces forces between two different substances, water between two different substances, water and paper or glass or xylem. and paper or glass or xylem.

Implication of Hydrogen BondingImplication of Hydrogen Bonding

Specific heatSpecific heat:: Water resists change in Water resists change in temperature. Heat energy is used to temperature. Heat energy is used to break H-bonds. Specific heat is amt. of break H-bonds. Specific heat is amt. of heat that must be absorbed or lost for 1 g. heat that must be absorbed or lost for 1 g. of the substance to change temp. by 1C.of the substance to change temp. by 1C.

Heat of vaporizationHeat of vaporization: amount of energy : amount of energy required to convert 1 gram of a substance required to convert 1 gram of a substance from a liquid to a gasfrom a liquid to a gas

the extraordinary properties of water courtesy of kate morkeski

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