Characteristics of Water

Where’s My Water?1. Fill a beaker with 100mL of water. This represents all water

on Earth.2. How much of the water do you think is contained in saltwater?

• Measure using the graduated cylinder.

3. Pour 97 mL of water into the graduated cylinder. 97% of all water is “trapped” as saltwater.• Dump out the 97 mL of water.

4. How much of the remaining water is in polar ice and glaciers? • Measure with the graduated cylinder.

5. Pour 2 mL of water into the graduated cylinder. 2% of all available water is in polar ice and glaciers.• Dump out the 2 mL of water

6. The remaining water represents the amount of freshwater on Earth. This includes water in reservoirs and lakes and underground.

Water:Covers ¾ of the Earth’s surface, but less than

half of one percent is available fresh waterSingle most abundant compound in most

living thingsExpands when freezes so ice is less dense

that waterhttp://

www.youtube.com/watch?v=2LAH7szGzJA

Chemical Properties of WaterThe Water Olympics

PolarityPresence of partial positive and negative charges causing attraction

• Due to an uneven distribution of electronics between the oxygen and hydrogen atoms

• Negative pole is near the oxygen and the positive pole between the hydrogen

• Greater probability of finding the shared electrons near the oxygen

Hydrogen Bonds: water glue•Hydrogen bonds occur in polar molecules containing hydrogen bonded to a highly electronegative atom (like water).

•The positive ends align with negative ends of other polar molecules

Does Soap Propel?How did that work?

Soap is an emulsifier.It interferes with the surface tension of water

by coming between water molecules

How Many Pennies?How did that work?

Water displayed cohesion and adhesion without the soap

When soap was introduced, it interfered with water cohesion and surface tension by coming between the water molecules.

Cohesion: attraction between molecules of the same substance

Adhesion: attraction between molecules of different substances

Capillary Action: tendency of water to rise in a thin tube

The Ventauri Effect: Fluids flow faster when forced through narrow spaces

Water OlympicsPenny DropsPour Water SidewaysWater StretchMerging StreamsWater TubesSoap Boat Race

Water: The Universal Solvent

MixtureA material composed of 2 or more elements or compounds physically combined

Solutions•If a crystal of table salt is placed in a glass of warm water, sodium and chloride ions on the surface of the crystal are attracted to the polar water molecules.

•Ions break away from the crystal and are surrounded by water molecules and become evenly distributed throughout (concentration).

Water’s Polarity Allows it to dissolve ionic compounds (ionic) and polar covalent compounds (sugar)

Hypothesize & InvestigateWhich compound, salt or sugar, will be more soluble in water?Why?

Water Has a High Specific HeatThe amount of energy needed to raise the

temperature of a substance 10CWater can absorb a large amount of heat

without significantly changing temperature.

Temperature and Earth’s Heat Budget LabUse Vernier to Analyze Graphs of Temperatures on Earth

Ice FloatsLess dense than water

Molecular motion slows during cooling allowing for formation of maximum number of hydrogen bonds

Crystal structure allows for air space

Air allows ice to insulate water below allowing for life to survive beneath

Frogsicles Project