1. WATER

2. Water is the solvent of Life!
Properties of Water
Universal Solvent
Water is the solvent of Life!
Solute – substance dissolved in a solvent to form a solution
Solvent – fluid that dissolves solutes
Example: Ice Tea – water is the solvent and tea and sugar the solutes

3. Cohesion, Adhesion and Surface Tension
Properties of Water
Cohesion, Adhesion and Surface Tension
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.
Ex: Think water in a straw
Ex: Water moves through trees this way

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.”
High Heat Capacity

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 So, can you name all of the 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
Figure 5-6

9. Salinity Salinity = total amount of solid material dissolved in water
Can be determined by measuring water conductivity
Typically expressed in parts per thousand (‰)
Figure 5-15

10. Constituents of ocean salinity
Average seawater salinity = 35‰
Main constituents of ocean salinity:
Chloride (Cl–)
Sodium (Na+)
Sulfate (SO42–)
Magnesium (Mg2+)
Figure 5-13

11. Salinity variations Location/type Salinity Normal open ocean 33-38‰
Baltic Sea
10‰ (brackish)
Red Sea
42‰ (hypersaline)
Great Salt Lake
280‰
Dead Sea
330‰
Tap water
0.8‰ or less
Premium bottled water
0.3‰

12. 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

13. Surface salinity variation
Pattern of surface salinity:
Lowest in high latitudes
Highest in the tropics
Dips at the Equator
Surface processes help explain pattern
Figure 5-20

14. 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

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

16. Water, Water Everywhere…

17. All freshwater comes from two sources:
Water that seeps below ground
Some is taken up and used by plants
Large amounts found in underground rock formations called aquifers
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
SURFACE WATER

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

19. 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

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

21. 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

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

23. 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

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

25. 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

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

27. Mississippi Watershed

28. 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

29. Stream Load Suspension Bed Load
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

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

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

32. Freshwater Ecosystems

33. 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

34. Lakes and Ponds

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

36. 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)

37. Freshwater Animal Adaptations

38. Freshwater Plant Adaptations