1. Science 8 Dedrick Messana Frank Hydrology Unit

2. Basics you need to know… Water is essential for LIFE Hydrosphere = 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 - ?

3. Basics you need to know… Water is the Universal Solvent It dissolves nutrients from rocks and soils It dissolves gases in the atmosphere Makes nutrients and gases more available to organisms on Earth

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

5. Forces of Attraction Cohesion = attraction of LIKE molecules water molecules sticking to water molecules Adhesion = attraction of molecules of DIFFERENT substances water molecules sticking to molecules of another substance

6. Phenomena caused by Forces Surface Tension = force on the top or outside edge of water, holding it in a tight bubble or droplet Caused by COHESION, water molecules want to cling to each other

7. Phenomena caused by Forces Capillary 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.)

8. DENSITY….very quickly…. Please put the following liquids in order from the LEAST DENSE (top)…to…MOST DENSE (bottom)!!! 1)Water 2)Karo Syrup 3)Lamp Oil 4)Honey 5)Vegetable Oil 6)Rubbing Alcohol 7)Dawn Dish Soap

9. Density D = mass / volume Density of water = 0.997 g/cubic cm (~1) Materials LESS DENSE than water will FLOAT in water Materials MORE DENSE than water will SINK in water Substances will layer as follows: Less Dense More Dense

10. 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

11. Dissolving Solute in Water Dissolving a substance in water will increase the density of the water More particles in the same space Objects will be more buoyant in salt water than fresh water Dead Sea!! 

12. Specific Heat Amount of energy needed to raise 1 gram of a substance by 1 degree Celsius Water has a HIGH specific heat = heats up and cools down SLOWLY Water is resistant to abrupt changes in temperature This trait protects aquatic organisms from temperature extremes

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