1. WATER

2. Water is the solvent of Life! Solute – substance dissolved in a solvent to form a solution Solvent – fluid that dissolves solutes

3. Properties of Water  cohesion = water attracted to other water  Molecules because of polar properties  adhesion = water attracted to other materials  Surface tension = water is pulled together creating  the smallest surface area possible

4. Properties of Water Capillary Action  Because water has both adhesive and cohesive properties, capillary action is present.  Capillary Action = water’s adhesive property is the cause of capillary action. Water is attracted to some other material and then through cohesion, other water molecules move too as a result of the original adhesion.

5. Properties of Water High Heat Capacity  In order to raise the temperature of water, the average molecular speed has to increase.  It takes much more energy to raise the temperature of water compared to other solvents because hydrogen bonds hold the water molecules together!  Water has a high heat capacity.  “The specific heat is the amount of heat per unit mass required to raise the temperature by one degree Celsius.”

6. Properties of Water Density  Water is less dense as a solid! This is because the hydrogen bonds are stable in ice – each molecule of water is bound to four of its neighbors.  Solid – water molecules are bonded together – space between fixed  Liquid – water molecules are constantly bonding and rebonding – space is always changing

7. Properties of Water  Adhesion  Cohesion  Capillary action  High surface tension  Holds heat to regulate temperature (High heat capacity)  Less dense as a solid than a liquid

8. The ocean moderates coastal temperatures  Water has high heat capacity, so it can absorb (or release) large quantities of heat without changing temperature  Moderates coastal temperatures

9. Salinity  Salinity = total amount of solid material dissolved in water  Can be determined by measuring water conductivity  Typically expressed in parts per thousand (‰)

10. Constituents of ocean salinity  Average seawater salinity = 35‰  Main constituents of ocean salinity:  Chloride (Cl – )  Sodium (Na + )  Sulfate (SO 4 2– )  Magnesium (Mg 2+ )

11. Processes affecting seawater salinity  Processes that decrease seawater salinity:  Precipitation  Runoff  Icebergs melting  Sea ice melting  Processes that increase seawater salinity:  Sea ice forming  Evaporation

12. Surface salinity variation  Pattern of surface salinity:  Lowest in high latitudes  Highest in the tropics  Dips at the Equator  Surface processes help explain pattern

13. Surface salinity variation  High latitudes have low surface salinity  High precipitation and runoff  Low evaporation  Tropics have high surface salinity  High evaporation  Low precipitation  Equator has a dip in surface salinity  High precipitation partially offsets high evaporation

14. Seawater density  Factors affecting seawater density:  Temperature ↑, Density ↓ (inverse relationship)  Salinity ↑, Density ↑  Pressure ↑, Density ↑  Temperature has the greatest influence on surface seawater density

15. All freshwater comes from two sources: Surface Water Lakes, ponds, rivers, and streams…ALL water above ground Most urban areas rely on surface water Supply resources and allow for travel/trade Ground Water Water that seeps below ground Some is taken up and used by plants Large amounts found in underground rock formations called aquifers

16. Surface water movement: Water Cycle  Earths water supply is constantly recycled

17. Surface Water Movement  1) Runoff  Water flowing down slope along Earth’s surface or seep into the ground  Run off speed determined by slope of the hill  Ends up in a stream or lake, evaporate, or accumulate into puddles

18. Movement  Seep into ground  Ground must have large enough pores – loose soil  Evaporate

19. Fate of water: Run off or Seep  Certain characteristics will determine whether not water will either seep into or become runoff  1) Vegetation  Vegetation allows for loose soil  Loose soil allows water to enter ground  Gardeners do not pack their soil

20. Fate of water  2) Rate of precipitation  Heavy:  Soil clumps together closing pores  Fills up ground to quickly and water becomes runoff  Light:  Allows water to gently slide through  Less erosion

21. Fate of Water  3) Soil Composition  Effects the waters holding capacity  Decayed organic matter (humus)  Creates the pores in soil – Increases retain ability  Minerals  Clay – fine mineral which clump together  Few Spaces  Sand – large pores

22. Fate of Water  4) Slopes  Steep: allows for high runoff & little absorption  Little: low runoff and high absorption

23. Formation of Stream systems  Runoff  Surface water flows in thin sheets and eventually collects in small channels  Runoff increases, channels widen and become deeper and longer  Channels fill up again each time with rain  Channel can become a stream

24.  Water sheds:  drainage basin  Land where all water drains into  Divide:  High land area that separates watersheds

25. Stream Load  All the materials that the stream carries  Solution  Material that has been dissolved  Depends on area where the steam runs through  Erosion of rocks and dirt

26. Stream Load  Suspension  Small particles held up by the turbulence of stream  Clay, silt, sand  Depends on volume and velocity of water  Bed Load  Turbulence of water pushes heavy things  Pebbles and cobbles  Larger velocity – large objects  B/c of abrasion, rocks are smooth

27. Stream Velocity & Carrying Capacity  Discharge = width x depth x velocity(m) (m) (m/s)  As discharge increases so does carrying capacity

28. Floods  Water fills over the sides of a stream banks  Floodplain: broad flat area of land that extends out from streams for excess flooding

29. Characteristics of a Freshwater Ecosystem  Slow moving waters  Low dissolved salt  Plant and animal life depends on depth of water, rate of flow, and amounts of nutrients, sunlight, and oxygen  Include lakes, ponds, rivers, and wetlands

30. Rivers  START in mountainous regions  Cold  Shallow beds  Highly oxygenated  A river’s characteristics changes with geography, climate, and the runoff from nearby developments

31. Wetlands  Covered in water at least part of the year  Trap and fix carbon  Control flooding and absorb extra water when other bodies overflow  Produce commercial products like seafood and berries (bogs)