Science 8Dedrick

MessanaFrank

Hydrology Unit

Basics you need to know…Water is essential for LIFEHydrosphere = all water environments on Earth

(oceans + water above ground+ water below ground + water in atmosphere)

Polar Covalent Molecule – has positive & negative end

Why is H +..and O - ?

Basics you need to know…Water is the Universal Solvent

It dissolves nutrients from rocks and soils

It dissolves gases in the atmosphereMakes nutrients and gases more

available to organisms on Earth

http://www.youtube.com/watch?v=0eNSnj4ZfZ8

Forces of AttractionCohesion =

attraction of LIKE moleculeswater molecules sticking to water molecules

Adhesion = attraction of molecules of DIFFERENT substances

water molecules sticking to molecules of another substance

Phenomena caused by ForcesSurface Tension = force on the top or

outside edge of water, holding it in a tight bubble or dropletCaused by COHESION, water

molecules want to cling to each other

Phenomena caused by ForcesCapillary Action = water moving

upward against the force of gravity in a narrow passageway, along the surface of a solid substance (hmm…where else?)

Caused by ADHESION, water molecules clinging to another substance (EX: side of a pipette, graduated cylinder, plant roots/stem, etc.)

DENSITY….very quickly….Please put the following liquids in order from the LEAST DENSE (top)…to…MOST DENSE

(bottom)!!!1)Water2)Karo Syrup3)Lamp Oil4)Honey5)Vegetable Oil6)Rubbing Alcohol7)Dawn Dish Soap

DensityD = mass / volume Density of water = 0.997 g/cubic cm (~1)

Materials LESS DENSE than water will FLOAT in water

Materials MORE DENSE than waterwill SINK in water

Substances will layer as follows:Less Dense

More Dense

Buoyancy

Force that works against gravity to allow objects to float in a liquid

Less dense materials float in more dense materials because of buoyancy

The MORE DENSE the liquid, the easier an object will float in it

The LESS DENSE the liquid, the less likely an object will float in it

Dissolving Solute in WaterDissolving a substance in water will

increase the density of the waterMore particles in the same space

Objects will be more buoyant in salt water than fresh water

Dead Sea!!

Specific HeatAmount of energy needed to raise 1 gram of

a substance by 1 degree CelsiusWater has a HIGH specific heat = heats

up and cools down SLOWLYWater is resistant to abrupt changes in

temperatureThis trait protects aquatic organisms from

temperature extremes

https://www.youtube.com/watch?v=gTqLQO3L4Ko