Water

1. Water An Environmental Perspective

2. Main organs Water content in % Brain 75 Blood 92 Bone 44 Heart 75 Kidney 83 Liver 86 Lung 86 Muscle 75 Why is water so important? • Water covers nearly 75% of the earth • Less than 1% of this is accessible • 65- 70% of your body is water.

3. Important Properties of Water Six reasons why water is the wellspring of life!

4. Strong interactive forces hold each water molecule to every other water molecule • This is a force between molecules. • This intermolecular force is the strongest intermolecular force. • It is called a hydrogen bond but it is not truly a bond. *

5. Wide temperature range for liquid • Because of the hydrogen bonding force, the molecules of water require much more energy to heat them to a boiling point. • Compared to other liquids with this molar mass (mass of one mole of the substance) the 100 degree C range for the liquid is quite large. *

6. Water can hold large amount of heat without change in temperature • When you walk on a sandy beach on a hot, summer day, which is hotter—the water or the sand? • Do both the water and sand receive the same amount of heat from the sun? • Why is the water so much cooler? • Water has a large specific heat • Specific heat is the amount of energy it takes to heat one gram of a substance one degree Celsius *

7. Many compounds will dissolve in water • Water is a polar substance. This means that it will dissolve all other polar substances and the majority of ionic (metals bonded to nonmetals like salts—NaCl) • Nonpolar substances like oils, greases, and waxes will not dissolve in water but nearly everything else will. • So many things dissolve in water that it has been dubbed the universal solvent *

8. Water has a high surface tension • Have you ever filled a cup above full so that the water actually created an arch above the cup? How can water do this? • Water’s strong hydrogen bonding forces create a strong surface tension for water. *

9. Water expands when frozen • Why do sealed containers that contain water explode when frozen? • Have you ever noticed that sealed containers that contain water that are intended to be frozen have less water and room for expansion? • This is due to the unique open structure that water forms when frozen. • This also allows ice to float in water. • What would be the consequences environmentally if ice did not float? *

10. Supply, Renewal, and Use Of water as a resource

11. Surface Water • Water that doesn’t go into the ground nor evaporate*

12. Watershed or Water Basin • A place from which water flows into • Example: a river, stream, or reservoir • What is your “watershed address”?*

13. Groundwater • Water from precipitation that goes into soil or rock *

14. Aquifers • Large, open areas in rock that are filled with water • Many aquifers are tapped for wells. *

15. Dissolved Oxygen (DO) content • Amount of dissolved oxygen in a given volume of water at a particular temperature and pressure • The higher the amount of DO the more diversified the aquatic community should be • Bottom dwelling organisms have very low need for oxygen. *

16. Salinity • Amounts of various salts that have been dissolved in a given amount of water *

17. The water cycle The hydrological cycle*

18. Steps of the Water Cycle • Leave room beneath each of these to write a description which will appear later • Precipitation • Infiltration • Percolation • Ocean Storage • Evaporation • Transpiration*

19. Water Cycle

20. The water cycle • Precipitation—water from the clouds or atmosphere to the lithosphere (can be rain, fog, snow, sleet, ice, or hail)*

21. Infiltration • Infiltration—precipitation which is absorbed by the ground*

22. Percolation • Percolation—a process that filters and cleans the water naturally; this could be water from precipitation or bodies of water or run off*

23. Water Cycle (cont.) • Ocean Storage—reservoir for water; the water in this basin is undergoing constant change in the water cycle*

24. Evaporation • Evaporation—water is evaporated from water storage areas*

25. Transpiration • Transpiration—water is given off by trees and green vegetation*

26. The cycle begins again • Evaporation and Transpiration give water back to the atmosphere where it condenses into clouds and then can return in the form of precipitation.*

27. Aquatic Life Zones Factors Layers and Regions*

28. Two factors that define an aquatic life zone • 1. Salinity—salt water content • Brackish • Saltwater • Freshwater • Dissolved Oxygen Content High amounts of DO mean that there would be a high amount of biodiversity Low amounts of DO would usually mean a very restricting level of organisms could live there. *

29. Water Resource Problems Freshwater Shortages*

30. Fun Facts about Water and Population • Canada’s population is about 0.7% of the world’s population. • Canada contains about 20% of the world’s fresh water supply. • China’s population is about 20% of the world’s population. • China contains only about 7% of the world’s fresh water supply. *

31. How are we running low on water with so many oceans?

32. Reasons for freshwater shortages • Dry climate • Drought • Desiccation • Water Stress (poor use of water as a resource)*

33. Solutions for Water Shortages How to avoid freshwater shortages*

34. Solutions to freshwater shortages • Build dams and reservoirs • Bring in surface water from other areas • Withdraw ground water • Desalination—removal of salt from saltwater or brackish water • Improved water efficiency*

35. Water Pollution Where do you think this picture was taken? Definition of water pollution Classes of water pollution*

36. Definition of Water Pollution • Any chemical, biological, or physical change in water quality that has a harmful effect on living organisms*

37. Classes of Pollution • Disease-Causing Pollution • Water borne diseases kill 10 million annually.*

39. Cheapest way to clean the water—The Sodis Method • Plastic bottles! • Fill a plastic bottle with water • Shake the bottle • Put the water in direct sunlight (UV light) for 6 hours*